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The Ultimate Sacrifice is the nineteenth episode of the third season of Ben 10: Ultimate Alien, and the thirty-ninth episode overall.


Ben as Humungousaur and the rest of the team are fighting a robot in the middle of the streets. After the robot takes out Kevin, it begins strangling Humungousaur, so Humungousaur transforms into Ultimate Humungousaur to fight the robot, and proceeds to annihilate it. Both Gwen and the robot beg Ultimate Humungousaur to stop, only for him to angrily shout out that he's not Ben.

Sentient Ultimate Humungousaur taking control of Ben

Suddenly, Ultimate Humungousaur attacks Gwen and Kevin. Gwen gets worried and notices that Ultimate Humungousaur's eyes are red. She tells Kevin that she thinks that Albedo might be controlling him, but Kevin thinks he just hit his head.

A conversation between Ben and Sentient Ultimate Humungousaur follows. They keep arguing about whose body it is. Kevin gets annoyed and hits Ultimate Humungousaur with a car so hard that he is sent flying into the distance. Gwen thinks she could turn him back to Ben and uses her spellbook to find the right spell.

After she uses the spell, they see Ben hitting himself with his eyes still glowing red. Gwen uses a sleeping spell to put him to sleep but he transforms back into Ultimate Humungousaur. Kevin ties him up with metal cables and Gwen calls Dr. Borges, a therapist, to see what's wrong with Ben.

Kevin, Gwen, and Dr. Borges

She asks him if he has issues with his mom when he was young. Sentient Ultimate Humungousaur replies that his mother tries to eat him before he even hatched. She tries to hypnotize the two personalities so that they can resolve their issues in their sleep and asks what he dreams of.

Sentient Ultimate Humungousaur answers and says that he's going to kill Ben. He breaks his arm free from the steel wires and chokes himself, attempting to kill Ben. His eyes glow green and Ben shouts out that he's killing both of them.

Gwen using her magic abilities on the Ultimatrix

After succesfully putting both Ben and Sentient Ultimate Humungousaur into a hypnotic trance Sentient Ultimate Humungousaur wakes up almost immediately and rips apart the cables roaring aggresively making Dr. Borges to get scared and runs away, asking them to pay for her work later. Sentient Ultimate Humungousaur shouts that his head is hurting and a few seconds later Sentient Ultimate Humungousaur glows red and Ben disappears, and leaving behind the Ultimatrix apparently turned off. Ben is sucked inside the Ultimatrix, thinking that he is dead.

Meanwhile, with Gwen and Kevin, Gwen argues with Kevin about how to get Ben back. Kevin figures out that Ben is inside the Ultimatrix. Gwen thinks that they should go in after Ben, but Kevin thinks that they would be trapped in forever. He decides that she can take the risk if she wants to, but she has to be careful. Gwen sends her Anodite astral projection form into the Ultimatrix, while Kevin goes and finds Azmuth for help.

Ghostfreak's debut in Ultimate Alien

Back to Ben, he is convincing himself he cannot be dead, because of his heroism and his handsome face and charms, when suddenly there is a short earthquake and from under the earth come out Sentient Ultimate Echo Echo, Sentient Ultimate Spidermonkey, Sentient Ultimate Swampfire, Sentient Ultimate Cannonbolt, Sentient Ultimate Big Chill, and finally Sentient Ultimate Humungousaur.

Ben is shocked and Sentient Ultimate Humungousaur reveals that the Ultimate Forms want to kill him in order to set them all free from the Ultimatrix. Ben quickly explains that they can't do that because they are all him. Sentient Ultimate Echo Echo calls Ben a liar, and screeches at Ben. Sentient Ultimate Swampfire said that they have brains and hearts like any other life forms have and that they are all alive.

Sentient Ultimate Spidermonkey webs up Ben and Sentient Ultimate Humungousaur drags him away, intending to throw him into a fire pit which will kill him and set them all free. Ben transforms into Ghostfreak to free himself from the web and tells them that they could try all they want. He tries to possess Sentient Ultimate Humungousaur, but is not able to.

Sentient Ultimate Big Chill uses his ice flames on Ghostfreak to freeze him (Ben as Ghostfreak couldn't escape as both of them were intangible), so Ghostfreak transforms into Heatblast to melt the ice, then transforms into Brainstorm and runs away. Brainstorm then transforms into Diamondhead and fights them. All of the Ultimates overpower him, so Diamondhead is forced to revert back to Ben.

Way Big vs. the Sentient Ultimates

Gwen's full Anodite form comes and takes them out to save Ben. Ben says that he had enough of being nice to them and transforms into Way Big and throws Sentient Ultimate Big Chill and Sentient Ultimate Echo Echo into an Ultimatrix like building and slams the others down into the ground.

Sentient Ultimate Humungousaur then calls out a retreat. Sentient Ultimate Big Chill questions his retreat idea, but after realising what he was planning everyone retreats leaving Way Big and Gwen alone.

Meanwhile, Kevin is flying the Rust Bucket 3, approaching Galvan Prime when a giant hologram recording of Azmuth's head appears, warning that if the unidentified ship came any closer, it would be destroyed. Kevin thinks that nothing will happen, but although he was able to dodge the automatic security system, he crashed the Rust Bucket 3 and blew it up.

Kevin fights a Galvanic Mechamorph

He saw that Azmuth's tower is close but when he got closer to the door, a big Galvanic Mechamorph came and told him he can't pass, so he got ready for a fight. Back to Ben (as Way Big), he was walking around, looking for a way out, with Gwen flying next to him.

Way Big asks Gwen what is with the glowy body. She tells him that her astral form was the only way to get into the Ultimatrix. Ultimate Spidermonkey captures Gwen in a web, but she just burns it off. The Ultimatrix times out and Way Big transforms back into himself, so the Ultimate Forms ambush him and take him by force. Gwen tries to get closer to save him, but Sentient Ultimate Echo Echo throws his sonic disks at her, which caused a distraction.

Meanwhile Kevin is still fighting the Mechamorph Guard. Kevin gets defeated, but he tries to explain to Azmuth that Ben saved the world countless times, he said so that he could let him in to save him, his best friend.

Suddenly, he sees Azmuth behind him telling the Galvanic Mechamorph to leave and tells Kevin that he will help. Back to Ben, Gwen was distracted by Sentient Ultimate Echo Echo's Sonic Doom attack. While she was being stalled by Ultimate Echo Echo, Ben was about to be thrown in a pit of fire by the Ultimates so that they could be set free.

Gwen suddenly gets really angry and blows up the sonic discs. She starts unleashing more of her immense Anodite power, But Ben begs her to stop, because she could lose her humanity. She says that she will no longer be under an immense power surge (so she gets to keep her humanity) and tells Ben that she is going to destroy all the Ultimates.

The Ultimates realize their fate, but just before Gwen destroys them, Ben orders her to stand down. He willingly wants to ultimately sacrifice himself so he can set his Ultimates free. Ultimate Humungousaur grabs Ben, and takes him to the pit of laser fire. Ben asks Sentient Ultimate Humungousaur whether he could have a last word with Gwen. He hesitates, but yet he trusts that Ben won't trick them.

So he lets him go to Gwen. He tells Gwen that he has to die. Gwen begs him not to do so, but Ben tells her to keep quiet. He said that a true hero will sacrifice for the sake of others and that he must die, if he wants to set the Ultimate forms free to live their lives and then gives Gwen a goodbye kiss on her forehead.

Ben kisses Gwen on the forehead to say goodbye

He walks to the pit of fire with the Ultimate forms around him, chanting the word "Burn". Before Ben jumps in, he stops to tell them that he never intended them to suffer. He takes one breath, waits, and jumps in.

The camera showed him waking up out of the Ultimatrix with Gwen, Kevin, the Ultimate Forms, and Azmuth around him. He was confused and told Azmuth that he died, Azmuth tells him due to his heroic sacrifice, the Ultimatrix set the Ultimates free and spared Ben's life.

Ben, Gwen, Kevin, and Azmuth in the end

He also tells Ben, while fixing the Ultimatrix, that the glitch that caused the Ultimates to gain consciousness has been removed and they will now be a reflection of Ben, as with all his transformations. This tells Ben that they are sorry for what happened in the Ultimatrix, but Ben said he had no hard feelings. Azmuth then creates a portal to take the Ultimate Forms to a planet where they would live in peace. Before they all leave, Sentient Ultimate Humungousaur apologizes to Ben and states that he wasn't as bad as he thought, before leaving himself.

Ben seems proud of himself by the expression on his face at the end of the episode and Kevin invites Ben and Gwen for a visit to Burger Shack. Gwen is surprised, but Kevin says that it's the least he can do for his "best girl" and his "best friend".

Noteworthy Events

Major Events

  • A glitch in the Ultimatrix caused some of the Ultimate Forms to become sentient. They attempted to kill Ben, as they thought they were being enslaved.
  • Azmuth fixes the glitch in the Ultimatrix and finally forgives Ben for hacking into the Omnitrix.
  • The Rust Bucket 3 is destroyed.

Character Debuts

Ultimatrix Alien Debuts

Minor Events

  • As a courtesy, the Ultimates have been taken by Azmuth to a nice planet to live freely.




Aliens Used

Spells Used

  • Imperium in mentum
  • Somnus



Dr. Borges: Tell me something about your relationship with your mother.
Sentient Ultimate Humungousaur: My mother tried to eat me before I even hatched!
Dr Borges: O...kay... there are probably some issues around that.

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Ben: I'm too young to die. And too famous, not to mention handsome and smart and talented. And charming, let's not forget that! But, if I am dead, chances are the place with the fiery red light is not where I wanna go!

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Kevin: I hate recordings, almost as much as I hate people telling me what to do!

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Kevin: Tennyson may have messed up the Ultimatrix, but he's put himself on the line again, again. He's risked his life a hundred times for people he didn't even know, for slobs like me, for jerks like you. He's a hero, and more important...he's my best friend.

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Ben: (Transforms into Ghostfreak)
Ghostfreak: Ghostfreak! (Phases through Ultimate Spidermonkey's web) Now, you're under my control! (Bumps into Sentient Ultimate Humungousaur's chest)
Sentient Ultimate Humungousaur: (Laughs) You don't understand anything, do you Tennyson? You can't control us! Not ever again!
(Ultimate Big Chill freezes Ghostfreak, who then becomes Heatblast)

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Kevin Levin: It's the least I can do for my best girl. And my best friend.

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Naming and Translations

Language Name Origin
Hungarian A végső áldozat The Ultimate Sacrifice
Portuguese (Br) O Sacrifício Supremo The Supreme Sacrifice
Spanish (HA) El Sacrificio Supremo The Supreme Sacrifice


Voice Actor Role(s)
Yuri Lowenthal Ben Tennyson
Red Robot
Ashley Johnson Gwen Tennyson
Greg Cipes Kevin Levin
Dee Bradley Baker Humungousaur
Ultimate Humungousaur
Way Big
Sentient Ultimate Humungousaur
Sentient Ultimate Spidermonkey
Sentient Ultimate Swampfire
Sentient Ultimate Echo Echo
Sentient Ultimate Cannonbolt
Sentient Ultimate Big Chill
Mechamorph Guard
Jeff Bennett Ghostfreak
Yeni Álvarez Dr. Borges


  • Through the entire episode, Sentient Ultimate Humungousaur claws are grey instead of black.
  • Even though the Ultimatrix created Ultimate Humungousaur, Sentient Ultimate Humungousaur mentions having a mother.
  • When Sentient Ultimate Humungousaur disappears into the Ultimatrix, the black switch on the Ultimatrix is not there.
  • Ben has an Ultimatrix even though he is inside the Ultimatrix itself.
  • Ghostfreak's hologram faces away from Ben.
  • Ghostfreak's back line pattern changes twice.
  • The lines on Heatblast's body are different when he is in the ice.
  • Way Big is once again smaller than usual.
  • In the final scene, Sentient Ultimate Echo Echo looks smaller.
  • When Azmuth fixes the Ultimatrix, for a split second, part of his jaw is in front of the watch.


  • The episode's title is listed as Ultimate Sacrifice on the back of the Ben 10 Ultimate Alien: The Wild Truth DVD.
  • Even though the synopsis of this episode said that all of the Sentient Ultimate Forms want freedom, Ultimate Wildmutt's sentient counterpart does not appear at all.
  • This is the fifth time an alien takes control of Ben, and the only time that it is an Ultimate Form who does this.
  • Azmuth took the Sentient Ultimates to his lab.[ES 1]


T.J. Collins

Eugene Son

Ben 10: Ultimate Alien Episodes