List of Ben 10: Ultimate Alien episodes

The following is a list of episodes of the American animated television series Ben 10: Ultimate Alien. A total of fifty-two episodes were ordered: 20 for the first season, 32 for the second season and 1 crossover

Series overview

Season		Episodes	Originally aired
			First aired	Last aired
	1	20	April 23, 2010 (2010-04-23)	December 10, 2010 (2010-12-10)
	2	32	February 4, 2011 (2011-02-04)	March 31, 2012 (2012-03-31)
	Crossover	1	November 25, 2011 (2011-11-25)	November 25, 2011 (2011-11-25)

Episodes

Season 1 (2010)

No. in series	No. in season	Title	Directed by	Written by	Original U.S. air date	Production code
1	1	"Fame"	Dan Riba	Dwayne McDuffie	April 23, 2010 (2010-04-23)	101
Ben's secret identity is revealed to the entire world, and he is now a superhero loved everywhere by kids and teenagers, but distrusted by many adults. Kevin and Gwen find out who revealed Ben's secret and where he lives, and the three go to "pay him a visit". The informant turns out to be a young boy named Jimmy Jones, who has followed Ben's exploits ever since he was ten-years old. With Jimmy's help, Ben and company discover a series of alien attacks in Florida. The unknown alien steals a nuclear device from a prototype interstellar rocket. They follow the alien to his ship, which he intends to launch using the nuke, which would destroy central Florida. Ben fights him as Spider-monkey, but proves to be too strong for him, so Ben turns into Ultimate Spidermonkey, with the Ultimatrix, defeating the alien with ease. Once defeated, the alien, Bivalvan, reveals he is from the Andromeda Galaxy who was kidnapped by an alien named Aggregor. He is left restrained, with assurance that the Plumbers will be along to bring him back home. Ben reluctantly returns to school with some encouragement from Julie. The students greet him with applause, including his old bullies Cash and JT. Meanwhile, Bivalvan is found and recaptured by Aggregor. Ultimatrix Alien Debuts: Humungousaur (Ultimate Alien debut), Jetray (Ultimate Alien debut), Chromastone (Ultimate Alien debut), Spidermonkey (Ultimate Alien debut), Ultimate Spidermonkey (official debut)
2	2	"Duped"	Butch Lukic	Len Uhley	April 30, 2010 (2010-04-30)	102
After trashing a Plasma Beam Tank belonging to the Forever Knights, Ben decides he needs to be in three places at once: 1) go to Julie's tennis game, 2) He has to fight the Forever Knights with Kevin, and 3) see the Sumo Slammers 3D movie. Using Echo Echo, he divides himself into three copies and transforms back into human form, creating three of himself. However, each is one part of his personality: one is logical, one is sensitive, and one is immature and insensitive. The sensitive Ben goes with Kevin to the museum, the insensitive Ben stays to watch Julie's match, and the logical Ben goes to see Sumo Slammers. Insensitive Ben proceeds to embarrass Julie while sensitive Ben cannot properly fight. When the Forever Knights steal a Aztec Battle Armor, Ben calls in his other selves for assistance, only to quickly realize that none of them are good fighters alone. He recombines into one and uses Lodestar to separate the armor, destroying it. Ben tries to apologize to Julie, which she almost accepts, until he admits he already went to see the Sumo Slammers movie when she suggests they go see it. Furious with Ben, Julie storms off with Gwen and Kevin right behind her leaving him alone to repent for what he has done in order to gain back their trust. Ultimatrix Alien Debuts: Rath (Ultimate Alien debut), Echo Echo (Ultimate Alien debut), Big Chill (Ultimate Alien debut), Upchuck (Ultimate Alien debut), Cannonbolt (Ultimate Alien debut), Lodestar (Ultimate Alien debut)
3	3	"Hit 'Em Where they Live"	Matt Youngberg	Len Wein	May 7, 2010 (2010-05-07)	103
Ben's enemies are targeting his parents now that he's famous. Max, unable to deal with them alone following a fight with Sevenseven, has to enlist Ben's aid. Vulkanus, Charmcaster, and Zombozo try to attack Ben's dad, Carl, but Ben, Gwen, and Kevin intercept them. Realizing that, as a team, Ben and his friends are too strong to beat, Zombozo decides to "divide and conquer". He kidnaps Ben's mother, Sandra, knocking out Gwen who tried to protect her, and hides her in a carnival to lure the team out and separate them, but Ben and Kevin manage to beat Vulkanus and Charmcaster respectively, with Ben using Ultimate Big Chill. Gwen is left to fight Zombozo, and briefly uses her Anodite form to intimidate him into leaving the Tennyson family alone and to spread the word to every other villain. Ultimatrix Alien Debuts: Swampfire (Ultimate Alien debut), Ultimate Big Chill (official debut)
4	4	"Video Games"	Dan Riba	Eugene Son	May 14, 2010 (2010-05-14)	104
While Gwen and Kevin are fighting each other about bad driving teaching of Kevin, Ben's celebrity status lands him in a starring role in a video game. Using motion capture technology, they record the moves of his various alien forms to integrate them into the game. In reality, however, the video game offer is a ruse by TV reporter Will Harangue and his assistant Oliver as part of his plan to create a robot to defeat Ben. After defeating Ben twice and trashing his reputation, Harangue challenges Ben to a final showdown on live TV. Unable to defeat the robot conventionally, Ben realizes what Harangue has done and uses Nanomech, the one alien he couldn't get data on, to destroy the robot from within. Ultimatrix Alien Debuts: Four Arms (Ultimate Alien debut), Nanomech (Ultimate Alien debut), Way Big (Ultimate Alien debut)
5	5	"Escape from Aggregor"	Butch Lukic	Charlotte Fullerton	May 21, 2010 (2010-05-21)	105
A turtle-like alien is causing a rampage in Bellwood. After managing to draw Ben out, who uses Ultimate Big Chill against him, and once Gwen convinces them to use the translators in their badges, he explains that he determined this to be the easiest method of finding Ben. The alien, named Galapagus, tells of how he escaped from Aggregor alongside four other abducted aliens: Bivalvan, P'andor, Andreas and Ra'ad. Aggregor had taken them each from their own home worlds in a plot to permanently absorb all of their unique abilities. Though the aliens escaped from Aggregor's spaceship, they crash-landed on Earth. After Ben's Ultimatrix scans Galapagus' DNA, he arranges for the Plumbers to get Galapagus back to his home planet. Unfortunately for Galapagus, Aggregor was impersonating the Plumber, and recaptures him. Ultimatrix Alien Debuts: Brainstorm (Ultimate Alien debut)
6	6	"Too Hot to Handle"	Matt Youngberg	Marty Isenberg	May 28, 2010 (2010-05-28)	106
P'andor (one of the aliens who were captured by Aggregor) offers a huge cash reward to anyone who can break him out of his containment suit. Kevin decides to take the job, only to back out upon learning that P'andor is highly radioactive. Ben tries to stop them as Ultimate Humuongosaur, but he manages to escape. Since Kevin has the ability to open the suit using his Osmosian powers to absorb Taedenite, P'andor tricks him into cutting it open. Free from his containment, P'andor begins feeding on all the energy he can find, making his way to a nuclear power plant. Ben uses Ultimate Cannonbolt and with Kevin's help is able to trap P'andor back inside his suit, and deliver him to a pair of Plumbers who offer to take him back to his home world. Unfortunately, Aggregor intercepts the Plumbers' ship in space and recaptures P'andor. Ultimatrix Alien Debuts: Ultimate Humungousaur (Ultimate Alien debut), Water Hazard (official debut), Ultimate Cannonbolt (official debut)
7	7	"Andreas' Fault"	Dan Riba	Ernie Altbacker and Jim Krieg	June 4, 2010 (2010-06-04)	107
When Ben, Kevin, and Gwen investigate an odd string of thefts by the Forever Knights, they learn that Argit is using Andreas (one of the aliens who were captured by Aggregor) to frighten the Forever Knights into making him their leader. Argit's plans go bad when the Forever Knights eventually revolt (under Sir Dagonet), and throw him into a dungeon with Ben and the others. When they discover that the Knights plan to execute Andreas, they break out and save him. As a last act of spite, Sir Dagonet sets a bomb that will destroy everything within five miles. Andreas sacrifices himself to absorb the force of the explosion. Although Ben and company believe him to be dead, Andreas survives and was recaptured by Aggregor. Ultimatrix Alien Debuts: Goop (Ultimate Alien debut)
8	8	"Fused"	Butch Lukic	Len Uhley	June 11, 2010 (2010-06-11)	108
After ambushing Ben at his house, Ra'ad (one of the aliens who were captured by Aggregor) after a short fight is thrown into a pool by Jetray. Electrocuted, he awakes in Los Selodad and blames Ben for letting Aggregor recapture the other four aliens. Aggregor has been tracking them through the Ultimatrix as a homing beacon each time it scans one of them. While trying to resist being scanned by the Ultimatrix, Ra'ad causes it to malfunction, and puts himself inside it, trapping both his and Ben's consciousnesses in the same body and turning off the Ultimatrix when Aggregor comes to capture Ra'ad, and Gwen uses a nonverbal teleportation spell to take them away after a brief fight. Despite Ra'ad's protests, Gwen and Kevin reactivate the Ultimatrix, and separate them. In doing so, they alert Aggregor to their location. Ra'ad flees, leaving the others to be wiped out by the Osmosian. After Kevin scolds Ra'ad for his cowardice, he decides to surrender himself to save Ben, and is recaptured by Aggregor. After the battle, Ben swears that he will do whatever it takes to save the captured aliens. Note: Gwen had used a high-level nonverbal teleportation spell. Ultimatrix Alien Debuts: Ampfibian (official debut)
9	9	"Hero Time"	Matt Youngberg	Steven Barnes	June 18, 2010 (2010-06-18)	109
Ben saves actress Jennifer Nocturne from a group of thugs and she is immediately smitten with him, much to Julie's chagrin. However, Ben's only interest is in Captain Nemesis, Ben's hero, who shows up moments after Ben defeats the thugs. Nemesis was actually responsible for hiring the thugs, having hoped to boost publicity by rescuing Jennifer. He tries again by releasing a group of dangerous robots led by Computron, only to be upstaged by Ben. After Ben casually comments on having defeated more of the robots than Nemesis, Will Harangue twists his comments into doubts about Nemesis' abilities. Nemesis decides to hold a friendly test of skill between them, and Ben again comes out on top. Finally pushed to the edge, he captures Julie and Jennifer, daring Ben to try and save them. Ben rescues Julie and they get back together again, while leaving Jennifer to Kevin and Gwen, then defeats Nemesis (now calling himself Overlord). Overlord is arrested, while Gwen is quick to discourage Jennifer from getting close to her most recent male rescuer. Will Harangue reports about Captain Nemesis' actions stating that a good man did bad things in order to stop "the menace that is Ben Tennyson." Ultimatrix Alien Debuts: Armodrillo (official debut)
10	10	"Ultimate Aggregor"	Dan Riba	Dwayne McDuffie	October 10, 2010 (2010-10-10)	110
With all five aliens in his possession, Aggregor tries to return to his home world, Osmos 5, to absorb all of their abilities. But a Plumber ambush damages his ship, so he instead heads for Los Soledad in order to use Paradox's time machine as an alternate power source. Despite Ben, Kevin, Gwen, and Grandpa Max's best efforts, Aggregor succeeds in absorbing the aliens' forms and powers, turning himself into an unstoppable amalgam of the quintet: Ultimate Aggregor. Ultimatrix Alien Debuts: Ultimate Swampfire (Ultimate Alien debut)
11	11	"Map of Infinity"	Butch Lukic	Dwayne McDuffie	October 10, 2010 (2010-10-10)	111
With his new powers, Aggregor easily defeats Ben and his friends. Azmuth tells Ben that Aggregor intends to steal the Map of Infinity, a complete map of the entire universe. With it, he'll be able to find the Forge of Creation, the birthplace of the universe. He further explains that Aggregor stole the five aliens' powers to protect him from the traps guarding the map, which was split into four pieces by Professor Paradox. In order to keep him from assembling the map, the team tries to take the first piece of the Map of Infinity first, which is at Mykdl'dy (A Necrofriggian (Big Chill's species) colony world made entriely of fire and ice. After a battle with the Necrofriggian guards, they go through the temple that houses the piece, getting past the traps, but are unable to retrieve the piece after Ben (as Fourarms) and Kevin are holding a door up, and Gwen is knocked out by a poison spike. Aggregor appears and thanks them for disabling the traps for him, and in a boost of anger, Ben holds the door himself, allowing them to escape. Ultimatrix Alien Debuts: Ultimate Echo Echo (Official Debut)
12	12	"Reflected Glory"	Matt Youngberg	Peter David	October 15, 2010 (2010-10-15)	112
Ben's childhood bullies, Cash and J.T. start a TV show with Oliver (who was fired by Will Harangue after what happened in "Video Games") as their cameraman, in which they claim to be the brains behind Ben's success as a hero. Ben, Gwen, and Kevin agree to play along after a sob story from the duo. Monitoring the broadcast, Vilgax's former assistant Psyphon is convinced the boys are responsible for his master's defeat and decides to kill them. During a mission to recover a Power Decoupler from the Forever Knights, Psyphon attacks, having augmented his abilities with Vilgax's technology and unleashes some R.E.D.s (Robotic Extermination Devices). Cash and JT are forced to admit their duplicity on camera to save themselves, so Psyphon turns his attention back to Ben. Ben cannot overcome him, even as Ultimate Spidermonkey, so Cash gets the idea to use the Power Decoupler on Psyphon, draining his power. Ben then knocks him out. Unfortunately for the duo, their act of heroism goes unnoticed, the weapon having knocked out the camera before firing, and their earlier confession has alienated their fanbase. Oliver leaves telling the boys that the show is over. Ultimatrix Alien Debuts: Terraspin (official debut)
13	13	"Deep"	Dan Riba	Marty Isenberg	October 22, 2010 (2010-10-22)	113
Ben, Gwen, and Kevin travel to the water world of Pisces (Ripjaws' home planet) after finding out that Aggregor is on the planet. Aided by Magister Pyke, they travel to the planet's core, which contains a gravitational multiplier holding the water planet together. Aggregor steals the device, which is actually a disguised piece of the Map of Infinity, and escapes, causing the inhabitants to mistake Ben, Gwen and Kevin as the thieves. To save the planet from floating into space, Ben transforms into Goop and uses his Anti-Gravity Multiplier as a replacement. Goop is atomized into the water of the planet, allowing him to draw all the lost water back in. With Pisces back to normal and their ship repaired, Ben, Gwen, and Kevin return to Earth.
14	14	"Where the Magic Happens"	Butch Lukic	Matt Wayne	October 29, 2010 (2010-10-29)	114
Gwen, Ben, and Kevin follow Aggregor into a mystical inter-dimension full magic and mana called Legerdomain with the help of Charmcaster, who was born there. They believe Aggregor's target to be the Alpha Rune worn by Addwaitya, ruler of Legerdomain, which they suspect is a disguised piece of the Map of Infinity. Gwen and Charmcaster work together several times, and the two develop a bond that seems to lead to Charmcaster changing her ways. While the group tries to steal the Alpha Rune, Aggregor uses the distraction to knock Addwaitya out and take it himself. Gwen, Ben, and Kevin escape Legerdomain with Charmcaster's help, but Charmcaster stays behind to free Legerdomain and her people from Addwaitya's rule. Ben promises Gwen that they will find a way to return and help Charmcaster after Aggregor is defeated.
15	15	"Perplexahedron"	Matt Youngberg	Brian Swenlin	November 5, 2010 (2010-11-05)	115
Azmuth was upset at Ben's failure to protect the first three pieces of the Map of Infinity, teleports Ben, Gwen, and Kevin to the fourth piece's location: a deadly artificial planet known as Perplexhahedron, created by Professor Paradox to destroy anyone who enters it. Ben, Gwen, and Kevin manage to fight their way through the traps. They are separated, and Gwen encounters Aggregor, but he simply ignores and leaves her in a freezing room. After that, Ben and Kevin accidentally find her there, then Gwen and Kevin kiss. They reach the Sentinel, who gives them the final piece. When the piece is taken, the whole planet starts to fall apart. The Sentinel stays behind, content that he has fulfilled his purpose in life, but Ben insists on rescuing him. However, Aggregor has found the Sentinel by the time Ben returns, and in the ensuing battle manages to take the final piece of the map from Ben, because he carried it back with him and dropped it. After getting back to the ship, the Sentinel, dismayed that his life amounted to nothing, vanishes into thin air. Though they've lost the battle, Kevin assures Ben that the war isn't over. Ultimatrix Alien Debuts: Ripjaws (Ultimate Alien debut)
16	16	"The Forge of Creation"	Dan Riba	Dwayne McDuffie	November 12, 2010 (2010-11-12)	116
Azmuth is still upset with Ben, Gwen, and Kevin for letting Aggregor get all of the four pieces of the Map of Infinity. Ben resolves to become Alien X to get Bellicus and Serena to cooperate. When this fails, Paradox arrives and changes Alien X back to Ben. After a brief argument, Paradox and Azmuth explain that the Forge of Creation is where all Celestialsapiens (Alien X's race) are born, and Aggregor hopes to absorb the powers and abilities of a newborn Celestialsapien and become omnipotent. Paradox takes them to the Forge of Creation, where an accident pulls Ben's ten-year-old self out of the timestream. After a few difficulties, past-Ben teams up with his future self to stop Aggregor. As they make their way through the Forge, they discover many Celestialsapiens in debate with themselves, and eventually a Celestialsapien egg. Aggregor reaches the egg at the same time the group does and takes everyone out with ease. In a last-ditch effort, Kevin absorbs energy from present-Ben's Ultimatrix, but the process drives him insane once again. He is now mutated like his old self, but has the new aliens instead of the old ones, becoming Ultimate Kevin. Kevin easily defeats Aggregor before absorbing his stolen power and attempting to kill him, only to be met with opposition from Gwen and both Bens. Past-Ben manages to get through to Kevin, who spares Aggregor's life before flying away, claiming he will not be so merciful next time. Paradox arrives at that moment to take them home before the other Celestialsapiens wake up, since he is not supposed to be near them, and return past-Ben to his own time period. Paradox claims that past-Ben will dismiss the entire experience as a dream while present-day Ben resolves to stop Kevin. Omnitrix Alien Debuts: Heatblast (10 year old Ben, Ultimate Alien debut), Wildmutt (10 year old Ben, Ultimate Alien debut), Four Arms (10 year old Ben, Ultimate Alien debut), Stinkfly (10 year old Ben, Ultimate Alien debut) Ultimatrix Alien Debuts: Alien X (Ultimate Alien debut), NRG (official debut)
17	17	"...Nor Iron Bars a Cage"	Butch lukic	Len Wein	November 19, 2010 (2010-11-19)	117
With Kevin having absorbed the Ultimatrix's aliens and gone back to his insane state, he returns back to the Null Void prison, Incarcecon. Ben and Gwen, searching for answers, realize they have to go to Incarcecon in an attempt to stop Kevin from killing the warden, Morgg. There are also flashbacks that Kevin has, how he left his first mutation and started to absorb solid matter both with the help of a fellow inmate named Kwarrel, and showed how he escaped from the prison, with Kwarrel sacrificing himself to Morgg in the process. Ben and Gwen soon realize that Morgg is forcing the prisoners to mine a blue substance which is sold as a hallucinogenic drug. Kevin manages to catch up with Morgg to exact his revenge, dropping him in an elevator and cutting the line. Gwen saves him and take him into custody, but by the time they hit surface, the prison is in ruins. Kevin fled the prison, and Ben thinks that Kevin may have to be put down, much to Gwen's shock and horror.
18	18	"The Enemy of My Enemy"	Matt Youngberg	Len Uhley	December 3, 2010 (2010-12-03)	118
Argit travels to Earth to borrow supplies from Kevin for a scam, where he discovers Kevin's condition and is nearly killed by the insane and vengeful Ultimate Kevin. Ben and Gwen send Argit to the Plumber's Academy to protect him from Kevin. While there Argit meets up with the Vreedle brothers (this particular set is training to be Plumbers to avoid being assassinated by their father again), where he explains that their father sent him there to rig their grades. Kevin then goes to the Plumber's Academy to kill Argit. Ben battles Kevin but cannot defeat him. Rhomboid then launches a nuclear fission bomb, which will destroy the Academy and everyone in it, but Ben uses Ultimate Echo-Echo to destroy the bomb. Kevin attacks Argit and seemingly kills him. When Gwen tries to stop Kevin, he attacks her, but does not kill her because of what she used to mean to him, suggesting there is hope for him still. After Kevin leaves, Ben reveals Argit is simply pretending to be dead (as his species can temporarily stop their pulse) and Argit is arrested by the Vreedle Brothers by the order of Magister Colonach.
19	19	"Absolute Power, Part 1"	Dan Riba	Charlotte Fullerton	December 10, 2010 (2010-12-10)	119
After Kevin absorbs the powers and abilities of Alan, Helen, Manny, Pierce, and Dr. Viktor, Ben and Gwen argue about the best way to deal with him. Ben decides to kill him, while Gwen argues that Kevin can still be saved. The argument escalates into a heated battle between the two first-cousins, which Ben wins as Way Big using an incredibly strong and powerful cosmic ray attack. He then starts looking for Kevin, attacking anyone who has ever had any criminal connections with him, including the Forever Knights and Vulkanus. Gwen, looking for an alternative, tracks down Darkstar. She convinces Darkstar to help Kevin, and in return, she gives him enough mana to retain his normal appearance for one year. Together with a newly matured Cooper, Darkstar devises a plan to save Kevin using a fragment of the Dominus Librium. He and Cooper build a machine in Los Soledad, using the left over pieces of both Aggregor's matter energy converting device, and Professor Paradox's time machine, to strengthen and amplify the piece's energy-draining abilities, thus restoring Kevin's sanity. Darkstar also devises a plan to have Kevin absorb a fraction of Gwen's magical and Anodite abilities so that he will hunt her for more.
20	20	"Absolute Power, Part 2"	Butch lukic	Dwayne McDuffie	December 10, 2010 (2010-12-10)	120
The first part of the plan is a success, but Cooper and Darkstar need more time to finish the machine, so Ben recruits his remaining allies, Grandpa Max, Julie, and Ship, to help hold him off. After a long standoff, Ben is able to use Ultimate Echo Echo to finally subdue Kevin and hook him into the completed machine. The machine restores an exhausted Kevin to normal. Suddenly, Darkstar uses the machine to drain the powers and abilities from Kevin into himself, glowing with almightly god-like power. Predicting this outcome in advance, Ben hits a kill switch on the machine that takes all the stolen powers from Darkstar, and gives them back to their rightful owners, in the process of returning Bivalvan, Galapagus, P'andor, Andreas, and Ra'ad to life. Ra'ad thanks them. Kevin and Gwen kiss. Then Kevin apologizes to Ben for his actions, and offers him a ride to Mr. Smoothie's to get a smoothie.

Season 2 (2011–12)

No. in series	No. in season	Title	Directed by	Written by	Original U.S. air date	Production code
21	1	"The Transmogrification of Eunice"	Matt Youngberg	Eugene Son	February 4, 2011 (2011-02-04)	201
Ben, Gwen, and Kevin go out into the wilderness for a camping trip. During a car race between Ben and Kevin, a strange pod falls from space. While trying to open the pod, Gwen cuts her hand on it. The pod then opens to reveal a beautiful, dark green-eyed, blonde-haired girl. Gwen gives the girl some of her spare clothes and the girl reveals her name to be Eunice, though she doesn't remember anything else. As the camping trip continues Eunice is revealed to have a strange connection to nature and Ben begins to develop romantic feelings for Eunice. Sunder then arrives on Earth on a mission to find Eunice. While Ben tries to take Eunice to see the ravine, Sunder appears and Ben and Eunice are separated. Ben, Gwen, and Kevin find Eunice at the ravine where Sunder activates a button on her neck, which turns her into a cylinder-like device (presumably an Omnitrix core). Ben stops Sunder from escaping with Eunice and Kevin returns Eunice back to her human form. As Eunice interrogates Sunder about her past, Azmuth appears and tells them that Eunice is actually one of his earlier prototypes of the Omnitrix, known as the Unitrix,(Uni as in one as opposed to Omni as in all.) and when Gwen had electrocuted her hand on the pod, the Unitrix absorbed her human DNA, creating Eunice, and that Sunder was freed from the Null Void by him to retrieve the Unitrix for him. Ben convinces Azmuth to not put Eunice into storage but to instead put her on Primus. Before leaving, Eunice gives Ben a blue-violet flower as a token of her intense romantic affections, and for him to remember her by.
22	2	"Eye of the Beholder"	Dan Riba	Len Uhley	February 11, 2011 (2011-02-11)	202
Baz-L is on a distant planet where he is stealing some valuable gems from some temple statues. Later, the temple guardian worshippers attack Baz-L. Ship suddenly hears Baz-L's cries for help, and leaves Julie to help his old owner. Julie ask Ben for help to locate Ship, who left to help Baz-L. However, their break-up makes things difficult, but Gwen and Kevin agree to help Julie. Ben realizes his mistake, so he transforms into Jetray and flies into space to chase after the Mecha-Vehicle. Gwen, Kevin, and Julie find Ship. Ship refuses to go back to Earth without saving Baz-L first. Ben arrives on the planet. Kevin tells Ben that the reason Julie broke up with him was because he was being a jerk. Soon they reach Baz-L, who is still being tortured by the one-eyed aliens to reveal the location of their precious artifact, the Occulent. The Sentinels, the statues, awaken and attack Ben and others for the Occulent. But it is revealed that Baz-El had eaten the Occulent, so Julie gives it back to the Sentinel and they go back to their stationary positions. Julie then gives Ship to Baz-L, saying that Ship would be happier with him. However, Ship decides to remain with Julie. Ben apologizes to Julie for being such a jerk and promises to make it up to Julie by trying to be a better boyfriend, which makes her happier again.
23	3	"Viktor: The Spoils"	Butch Lukic	Kevin Grevioux	February 18, 2011 (2011-02-18)	203
Zarcovia's soldiers has found the frozen body of Dr. Viktor (after the events of Absolute Power, where Ultimate Kevin attacked and absorbed his abilities). Prince Gyula and King Xarion want to see this weapon, Gyula wants to control Dr. Viktor to use him against rebels in their civil war, but Xarion tells him not to, King Xarion asks for help from Ben, Gwen, and Kevin and explains what Gyula is trying to accomplish. When they find Dr. Viktor's corpse, they are found by Gyula's soldiers, while fighting them, Dr. Viktor's ice block begins to melt and he breaks free, Gyula reveals that Dr. Viktor is under his control. Dr. Viktor defeats Ben, Gwen and Kevin and imprison them, along with King Xarion. Gwen manages to free Xarion, but he takes an unconscious Ben for his own plans. He conducts an experiment on Ben using AmpFibian's electrical abilities, Dr. Viktor, and himself, but Prince Gyula interferes in order to stop Xarion from taking control of Dr. Viktor. Unfortunately, King Xarion's subconscious mind has been transferred to Dr. Viktor's body King Xarion, now calling himself King Viktor, starts hurting Prince Gyula. He releases Gyula as a last act of mercy, starts attacking the rebels, and is defeated by Heatblast, Gwen and Kevin. Gyula and his soldiers try to take King Viktor back, but Ben takes Gyula's device that controls his soldiers and sets them free. King Viktor swears to Ben to take revenge. Ultimatrix Alien Debuts: Wildmutt (16 year old, Ultimate Alien Debut), Heatblast (16 year old, Ultimate Alien Debut)
24	4	"The Big Story"	Matt Youngberg	Ernie Altbacker & Jim Krieg	March 4, 2011 (2011-03-04)	204
Jimmy Jones sees a meteor falling in a cave. He goes in the cave and an alien plant attacks him. He tells Ben and his team about it, but only Ben believes him. They go in the cave but, the plant isn't there. Jimmy offers some peanuts to Ben, but he says that he is allergic. The next day, Jimmy sees Ben going into the cave and talking to the plant. He takes a photo of that, but the photo isn't good, so Gwen doesn't believe him. Later, Jimmy goes to the supermarket and Ben, as Humongousaur, attacks him. Jimmy takes his bicycle and runs, but Ben becomes Cannonbolt and hunts him down. Jimmy goes to Gwen and Kevin and they all go to the cave. In the entrance of the cave they catch Jimmy and they take him to the plant. Jimmy finds that Gwen, Kevin, and Ben are clones made by the plant. Jimmy remembers Ben's false allergies to peanuts and he throws his peanuts on the cages that the real Ben, Gwen and Kevin are in. Ben takes the Ultimatrix from his clone then he becomes Ultimate Swampfire and he destroys the Plant. After that, Gwen tells to Jimmy that they will take him more seriously next time.
25	5	"Girl Trouble"	Dan Riba	Eugene Son	March 11, 2011 (2011-03-11)	205
The team goes to Gwen's house to find a solution to defeat Computron's minions from Dimension 12. When they go to Gwen's room, they find a dark-hair girl. Gwen's mother, Natalie, tells them that it's Sunny, Gwen's naughty cousin. They try to leave the house, but Gwen's mom insists they take Sunny with them. The team takes Sunny to the mission but, they left her in Kevin's car. They go to fight the robots. Ben becomes Four Arms. Sunny gets bored in the car, and she follows them. She destroys the robots with ease. Sunny is very happy, but the team is looking at her strangely. Gwen tells her mother that Sunny is an Anodite, much to her surprise and disgust. Then, a big monster knocks on the door. It is Antonio, Sunny's lovestruck boyfriend. Gwen tries to stop Sunny from going with him, but fails. The team goes to defeat the robots, which have returned. During the fight, Sunny comes to have fun and she defeats some of the robots. When Gwen tells Sunny that her parents don't want her dating Antonio, Sunny sheds her human disguise and a fight ensues. Ben becomes Ultimate Humongousaur and defeats Antonio. Sunny proves to be far much stronger than Gwen, as she managed to immobilize Gwen with her long flowing tendrils of whitish-magenta hair easily. Gwen summons Grandma Verdona through a manna field, who comes and takes Sunny and Antonio back to Anodyne so that their parents can deal with them themselves.
26	6	"Revenge of the Swarm"	Butch Lukic	Stan Berkowitz	March 18, 2011 (2011-03-18)	206
Taking place one year after the events of "Alien Swarm", Victor Validus attacks Ben at night but when he defends himself, he finds a Nanochip that was believed to have been destroyed along with its Queen. Ben, Kevin and Gwen find Elena Validus to see what is going on.
27	7	"The Creature from Beyond"	Dan Riba	Len Uhley	March 25, 2011 (2011-03-25)	207
An old man named George watches TV. In fact, he is actually watching some Forever Knights live. The group of Forever Knights that he is watching tries to break an ancient seal. The Knights headed up by Sir Reginald knew that behind that seal was the secret of the First Forever Knight, and possibly a cache of alien tech. A squire named Winston tries to tell Sir Reginald that this is a bad idea, but they ignore him and continue to break the seal. A bright light suddenly shone from the cracks in the seal. Old Man George runs away from the TV and leaves his home. The team goes to the place that the Knights were and encounter another Forever Knights group led by Sir Cyrus (who claims that his group is much different from the Forever Knights led by Patrick, Urian and Driscoll). Gwen finds that a monster was sealed there. They find the monster which is a Limax-like medium-sized monster. The monster touches Gwen's head and Gwen enters its mind. A few minutes later, she goes in her mind again. Kevin in his metal form also has his head touched but it has no effect on him. At the end of the fight, the monster kidnaps Winston. Gwen learns that the monster is a Lucubra, a monster from another dimension. They find the Lucubra again, but they don't let Gwen join in the fight unless they need her (due to the mental after-effects the monster has on her). They go in, Ben becomes Armodrillo and the Lucubra attacks them. Just when Gwen is about to go in, Sir Cyrus with his group appears. They go in, Ben becomes NRG, and when Lucubra tried to attack his head the team discovers that metal is immune to the Lucubra's mind control. NRG opens a big hole and Gwen casts a nonverbal, high-level spell to transport the Lucubra back to its dimension. In the end, Old Man George goes to the door and discovers that the creature is not inside.
28	8	"Basic Training"	Butch Luck	Adam Beechen	April 1, 2011 (2011-04-01)	208
When Ben, Gwen, and Kevin battle Trombipular, an elephant-like alien, they are summoned to Plumbers Academy to go under training. They create a good friendship with an alien named Tack and Ben dislikes the drill instructor, Magister Hulca, that is being targeted for revenge by a menacing Tetramand. Ultimatrix Alien Debuts: Diamondhead (Ultimate Alien Debut), Fasttrack (Official Debut)
29	9	"It's Not Easy Being Gwen!"	Matt Youngberg	Matt Wayne	April 8, 2011 (2011-04-08)	209
Gwen must juggle things around, in which she has to help Ben and Kevin recapture Dr. Animo, fill out invitations for her mother Natalie's family reunion, help Kevin get into school, finish exams, and go to her best friend Emily's piano performance...all in one day.
30	10	"Ben 10,000 Returns"	Matt Youngberg	Dwayne McDuffie	April 15, 2011 (2011-04-15)	210
Following a visit from Paradox after a fight with Eon, Ben 10,000 arrives twenty years from the future to seek the aid of his sixteen-year-old past counterpart in tracking down Eon. It is revealed that Eon is actually an adult Ben from an alternate world, and that he wanted to destroy all of the other Bens to become the one and only Ben Tennyson. It was also revealed that the ten-year old Ben in "Ben 10: Race Against Time" is an alternate Ben as well, and not the Ben in "Ben 10: Ultimate Alien". Plus, the Ben 10,000 that Gwen and Ben met when they were ten isn't the same Ben 10,000 they meet in the episode. This thirty-six-year-old Ben 10,000 is actually the current Ben; two decades later. Ben 10,000 Omnitrix Alien Debuts: Ultimate Humungousaur (Official Debut), Articguana (Ultimate Alien Debut), Heatblast (Ultimate Alien Debut), Clockwork (Official Debut), Spidermonkey (Official Debut), Jetray (Official Debut), Diamondhead (Ultimate Alien Debut), XLR8 (Ultimate Alien Debut),
31	11	"Moonstruck"	Butch Lukic	Len Uhley	April 22, 2011 (2011-04-22)	211
In flashbacks, Max tells the astounding story to Kevin, Gwen, and Ben of how he had met and fallen head-over-heels for a supremely powerful female Anodite alien when he was but seventeen years old in the 1940s.
32	12	"Prisoner Number 775 is Missing"	Dan Riba	Peter David	April 29, 2011 (2011-04-29)	212
The secrets of Area 51 are revealed to Ben Tennyson by Colonel Rozum after Old George infiltrates and destroys it, setting free the 775th prisoner. Ultimatrix Alien Debuts: Ultimate Wildmutt (Official Debut), ChamAlien (Official Debut)
33	13	"The Purge"	Butch Lukic	David McDermott	September 16, 2011 (2011-09-16)	213
Driscoll, Urian, Enoch and Patrick are all sitting in the same room, eyeing each other with utmost loathing. Chaos erupts when Driscoll angrily berates that Urian is wasting his time by calling him in at dead of night, accompanied by the "heretics", until Old George arrives. He scolds them for separating the Forever Knights into different factions. Incensed, Driscoll warns George to "choose his next words carefully". He then orders his knights to attack Old George for his insults but are helpless against Old George's more technologically advanced Forever Knight bodyguards. Driscoll then attacks Old George himself but is defeated with very little effort by Old George. Then, Old George reveals his identity and Driscoll kneels before him, calling him "Founder of Our Order, The Original Forever Knight", followed by the other Forever Kings and their knights. Old George unites the Forever Knight factions into one and vows to rid the Earth of all aliens. Pierce, whose identity is hidden by an ID Mask, is romantically flirting with a girl but a group of Forever Knights come and demand that he leave Earth. They break his ID Mask, scaring the girl away and then kill him when he refuses to leave Earth. Meanwhile, NRG, Gwen, and Kevin are fighting Trumbipulor, who has escaped the Null Void. Despite their efforts, he escapes as Argit arrives in a shuttlecraft. He explains that the Forever Knights are trying to make him and other aliens leave Earth, and he needs their help to convince them to let them stay. Despite their lack of trust in him, they decide to look into his story. Finding that a few hundred aliens have indeed "left", they go to a Forever Knight castle to investigate. However, they accidentally activate the castle's security alarm; releasing another Dragon Robot, far much stronger than before. Lodestar and Kevin easily destroy the dragon. The group head to an alien food market to investigate and talk to the butcher Mr. Baumann to find out why the aliens are leaving. Mr. Baumann tells them that he has no idea, so Ben, Gwen and Kevin leave. They sneak back in and it is then revealed that he has been hiding an alien family from the Forever Knights. Mr. Baumann tells the gang that the Forever Knights have been attacking aliens on Earth. The team decides to set a trap and wait for the Forever Knights to show up at the date that a supply ship for the alien food market is coming. Soon, the gang is watching over a bunch of aliens as the supply ship comes, but some of George's knights arrive and attack the team. Ben (as Upchuck), Gwen and Kevin try to fight them off, but the Forever Knights outnumber them and a Plasma Beam Tank drives in and easily defeats Ben, Gwen and Kevin. Ben, Gwen and Kevin free themselves from the handcuffs they have been placed in and get ready to fight the Forever knights again, but Ben decides to challenge Driscoll to a duel, going from Spidermonkey to Ultimate Spidermonkey. Though Driscoll is gaining the upper hand, thanks to his armour, Ultimate Spidermonkey beats him and threatens him to free the alien he has captured as prisoners and get rid of the knights. The Forever Knights free the aliens and leave. Driscoll reports his failure to George, but George reassures him that he will not be punished and that this will be the beginning of a far greater war: "The battle of a hundred lifetimes".
34	14	"Simian Says"	Matt Youngberg	Charlotte Fullerton	September 23, 2011 (2011-09-23)	214
Simian accidentally unleashes a Xenocyte Queen which orchestrates an invasion of the Arachnachimps' planet. When Eunice goes missing, Ben, Gwen, and Kevin end up helping Simian liberate the Arachnachimps' planet from a DNAlien version of the Arachnachimp Mizaru. Note: Eunice affectionately kisses Ben on the cheek in this episode, as another implication of her more-than-friendly feelings for him.
35	15	"Greetings from Techadon"	Dan Riba	Charlotte Fullerton	September 30, 2011 (2011-09-30)	215
Techadon robots go after Ben on orders from Vulkanus to attain the Ultimatrix. Gwen and Kevin go across space to prevent Vulkanus from getting what he is after.
36	16	"The Flame Keepers' Circle"	Dan Riba	Brian Swenlin	October 7, 2011 (2011-10-07)	216
Julie joins a cult called the Flame Keepers' Circle. Unfortunately for her, Ben discovers that the Flame Keepers' Circle worships Vilgax; whom they mistake for the mighty Daigon because of his close squid-like resemblance.
37	17	"Double or Nothing"	Matt Youngberg	Len Uhley	October 14, 2011 (2011-10-14)	217
Albedo profits from Ben's fame and creates a play about him with the help of three alien actors based on the aliens in Ben's Ultimatrix.
38	18	"The Perfect Girlfriend"	Dan Riba	Stan Berkowitz	October 21, 2011 (2011-10-21)	218
Elena and the nanochips return and impersonate Julie while the real Julie is at a tennis tournament overseas. Ben does not catch onto this until the very end when the real Julie returns and causes Elena to realize that she had never really loved and cared about the real Ben in the first place. Now knowing what true hatred is, Elena disappears with a promise to return.
39	19	"The Ultimate Sacrifice"	Butch Lukic	Dwayne McDuffie & J.M. DeMatteis	October 28, 2011 (2011-10-28)	219
The ultimate aliens inside Ben's Ultimatrix demand their freedom and end up sucking Ben into the Ultimatrix. While Gwen assumes her inner Anodite form as her astral projection to enter the Ultimatrix to help Ben, Kevin travels to planet Galvan Prime to convince Azmuth to help. Ultimatrix Alien Debuts: Ghostfreak (Ultimate Alien Debut)
40	20	"The Widening Gyre"	Matt Youngberg	Eugene Son	November 4, 2011 (2011-11-04)	220
The gang look into the Pacific Garbage Vortex when some people have gone missing. When they arrive, they find the missing people and two agents sent by Colonel Rozum while dealing with giant seagulls and a sentient Trash Monster. Note: References to Captain Planet and The X-Files were made by Kevin when the gang lands on the Pacific Garbage Vortex. He describes them as shows he watched as a kid, "5 kids with the power to recycle" and "with the 2 agents who went around investigating weird stuff".
41	21	"The Mother of All Vreedles"	Dan Riba	Matt Wayne	November 18, 2011 (2011-11-18)	221
Ma Vreedle plans to spawn an army of Pretty Boy Vreedle clones, which could dry up Earth's oceans.
42	22	"A Knight to Remember"	Butch Lukic	Len Uhley & Matt Wayne	December 2, 2011 (2011-12-02)	222
Vilgax and the Flame Keepers' Circle fight against George and the Forever Knights along with Ben Tennyson. Vilgax gets Dagon's heart and ends up being sucked into Daigon's own parallel dimension. Ultimatrix Alien Debuts: Eatle (Official Debut)
43	23	"Solitary Alignment"	Matt Youngberg	Peter David	December 9, 2011 (2011-12-09)	223
Azmuth reveals in his memories how Old George had acquired the great sword, Ascalon, and how he sealed Daigon the first time millennia ago. In addition, he reveals the real reasons for creating the Omnitrix and the Ultimatrix.
44	24	"Inspector 13"	Butch Lukic	Geoffrey Thorne	February 4, 2012 (2012-02-04)	224
Techadon Weapon Master 13 arrives on Earth and demands to have the Ultimatrix. A malfunction grants Gwen and Kevin the forms and abilities of some of Ben's aliens. Ultimatrix Alien Debuts: Clockwork (16 year old, Official Debut),
45	25	"The Enemy of My Frenemy"	Matt Youngberg	David McDermott & Brian Swenlin	February 11, 2012 (2012-02-11)	225
With the help of Hex, Gwen and the gang set out to rescue Charmcaster from her home world of Ledgerdomain. But they are shocked to learn that Charmcaster's intentions bold ill for them all.
46	26	"Couples Retreat"	Dan Riba	Geoffrey Thorne	February 18, 2012 (2012-02-18)	226
Darkstar romantically charms Charmcaster and uses her magical strength and energy to his own evil advantage to absorb all of the infinite amounts of mystical mana from Ledgerdomain. Meanwhile, Gwen and Kevin have a disagreement over the protection of one of her spellbooks. Note: The title of the episode is referenced to a romantic comedy film "Couples Retreat."
47	27	"Catch a Falling Star"	Butch Lukic	Len Uhley	February 25, 2012 (2012-02-25)	227
Jennifer Nocturne runs away with Captain Nemesis after freeing him from jail in hopes of creating a new life with him.
48	28	"The Eggman Cometh"	Matt Youngberg	Stan Berkowitz	March 3, 2012 (2012-03-03)	228
Dr. Animo returns with a plot to transform eggs into pterodactyls. Ultimatrix Alien Debuts: Jury Rigg (Official Debut)
49	29	"Night of the Living Nightmare"	Dan Riba	Don McGregor	March 10, 2012 (2012-03-10)	229
Albedo returns and infects Ben with a Cassiopeian Dream Eater, trapping him into a dream world where he kept being attacked by several of his enemies. Eventually, when Albedo enters the dream posing as Kevin and Gwen in an attempt to take the Ultimatrix, Ben figures out it's really him and starts fighting him. As Ben starts taking over the dream world, Albedo attempts to put back the Dream Eater, only to slip on a spilled smoothie and accidentally end up being the one infected. In the real world, it was revealed that Ben was never infected, as Albedo slipped on a smoothie, thus replaying the same thing that happened in Albedo's nightmare. While they get him to a Galvan doctor in order to remove the Dream Eater, Albedo is seen inside the dream world, being confronted by some of the Ultimatrix Aliens and fearfully begs them to stay away as they come near him.
50	30	"The Beginning of the End"	Butch Lukic	Charlotte Fullerton & Eugene Son	March 17, 2012 (2012-03-17)	230
The Forever Knights battle Daigon's Esoterica and Ben's plan to help the knights fails as they are, too, intent on fighting him to listen to reason.
51	31	"The Ultimate Enemy, Part One"	Matt Youngberg	Matt Wayne	March 24, 2012 (2012-03-24)	231
Ben, Gwen, Kevin, and George try to stop Dagon's resurrection, but first, they must defeat the demon's herald: Vilgax, now merged with a Lucubra and is much stronger than ever. To make matters worse, Dagon releases a wave that transforms everyone on the planet into an Esoterica, save Ben, Gwen, Kevin, George, Julie, and Ship. Gwen is briefly turned against her allies due to her previous psychic enslavement by a Lucubra, but Kevin is able to restore her human mind. Unfortunately, the combined efforts of Vilgax and a possessed Gwen manage to break the seal, releasing Daigon at last.
52	32	"The Ultimate Enemy, Part Two"	Dan Riba	Dwayne McDuffie	March 31, 2012 (2012-03-31)	232
The monstrous squid declares his intent to conquer Ben's universe, and summons the Esoterica to destroy the heroes. Despite debuting his Ultimate Way Big form, Ben fails to defeat the extradimensional fiend, who proceeds to destroy Sir George by electrocuting him with dark lightning. All seems lost until Vilgax returns, capturing Diagon by Psyphon's power-absorbing machine. Before the heroes can stop him, Psyphon proceeds to transfer Dagon's power to Vilgax, making the galactic conqueror into a nearly-unstoppable force. Gwen warps Ben, Kevin and herself into the Plumber's base in Mount Rushmore to hide from Vilgax, but the newly-empowered villain tracks them down and has his horde of Esoterica attack. Gwen uses the base's defenses to repel the brainwashed humans, but Vilgax personally attacks the base and disables both Gwen and Kevin. Confronting his old foe, Ben wields George's sword, Ascalon, and uses it to drain Dagon's power from Vilgax. Reverted to his original form, Vilgax tries to corrupt Ben, asking what he plans to do with the combined power of Ascalon, Diagon, and the Ultimatrix. Ben declares his intent to revert the Esoterica into humans, but Vilgax derides him for thinking "too small"; with his new power, Ben could destroy all evil in the universe. Gwen and Kevin both encourage Ben to resist Vilgax's temptation, and Julie (in Ship's armor mode) arrives to further sway her friend away from the path of tyranny. Ben demands quiet as he considers his options, and after remembering his adventures, he uses his infinite godly abilities to transform the Esoterica back into humans. To everyone's surprise, Azmuth appears before them and asks Ben to return Ascalon and the Ultimatrix to him. Ben wonders if he has not yet proved his worthiness to the diminutive alien, but Azmuth corrects him; the Ultimatrix is no longer worthy of him. He gives Ben a new version of the Omnitrix; the "true" version Azmuth has been developing ever since he gave Ben the prototype six years ago. Cryptically suggesting that Ben may get the Master Control at a later date ("Perhaps on your eighteenth birthday"), Azmuth disappears, leaving the heroes to bask in victory. Afterwards, Azmuth deactivates the Ultimatrix because it was merely a prototype. Ultimatrix Alien Debuts: Ultimate Way Big (Official Debut) Note: This episode is dedicated to the memory of Dwayne McDuffie, one of the writers of Ben 10, who died on February 21, 2011 from complications from emergency heart surgery.

Ben 10/Generator Rex crossover (2011)

No. in series	No. in series	Title	Director	Writer(s)	Original airdate
53	Special 1	"Ben 10 / Generator Rex: Heroes United"	Chris Graham and Kenji Ono	Man of Action	November 25, 2011 (2011-11-25)
Ben goes through a rift to Rex Salazar's dimension. After quarrels with each other for a long time, the two finally work together to stop a threat once created by Rex's older brother, Caesar, the Alpha Nanite. Ultimatrix Alien Debuts: Shocksquatch (Official Debut), XLR8 (Ultimate Alien Debut), Upgrade (Ultimate Alien Debut)

DVD releases

Volume	Season	Aspect ratio	Episodes	Time length	Release date
1. Ben 10: Ultimate Alien – Escape From Aggregor	1	16:9	10 (Episodes 1–10)	223 minutes	January 11, 2011 December 1, 2010
2. Ben 10: Ultimate Alien – Power Struggle	1	16:9	10 (Episodes 11–20)	230 minutes	May 3, 2011 April 5, 2011
3. Ben 10: Ultimate Alien – The Return of Heatblast	2	16:9	10 (Episodes 21–30)	230 minutes	August 2, 2011 September 11, 2011
4. Ben 10: Ultimate Alien – The Wild Truth	2	16:9	12 (Episodes 31–42)	276 minutes	December 6, 2011 November 30, 2011
5. Ben 10: Ultimate Alien – The Ultimate Ending	2	16:9	10 (Episodes 43–52)	220 minutes	April 17, 2012 March 21, 2012

See also

• List of Ben 10 episodes
• List of Ben 10: Alien Force episodes
• List of Ben 10: Omniverse episodes