Characters / Ben 10: Omnitrix Aliens (Alien Force)

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Alien X

Alien X (AF-13)

"Motion Carried!"

Serena voiced by Vicki Lewis (Alien Force), Tara Strong (Ultimate Alien), Kimberly Brooks (Omniverse)

Bellicus voiced by Kevin Conroy (Alien Force), Jeff Bennett (Ultimate Alien), Eric Bauza (Omniverse)

Alien X was sampled from a Celestialsapien, a species of mysterious, god-like aliens with Reality Warping powers. Similar to Ghostfreak, Alien X is sapient of its own accord. It houses two distinct personalities: Serena, the voice of love and compassion, and Bellicus, the voice of anger and aggression. Both of them have near-infinite ability to channel just about any thought into reality, making this arguably Ben's most powerful alien. However, the arguable part is quite literally an issue, as Serena and Bellicus have totally opposite personalities that rarely find the time to actually use these incredible powers because they are obsessed with debating just about every matter there is to discuss and never agree on anything long enough to perform any sort of action unless someone intervenes, or they relent on some level.

This doesn't just apply to them; most Celestialsapiens are crippled by their multiple indecisive personalities, and it is rare to find one that can behave competently without arguing with itself, aside from the infants, which have yet to gain split personalities. Luckily, it's a good thing, because, under the wrong set of circumstances, they might just wipe everything out in the blink of an eye. They reside in a universe far beyond the normal confines of our own and are born from a truly gigantic in comparison Celestialsapien mother.

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• Adaptational Badass: This and the opposite trope below. Alien X in the reboot has a lot more control and ease of use, allowing the user to use extensive powers without the hurdles of multiple personalities and debate.
• Adaptational Wimp: This and the opposite trope above. Alien X in the reboot can do a lot of things: teleport, terraform planets, manipulate gravity, fire energy blasts...however Alien X does not have the sheer reality warping he does in the classical continuity. He also can be overpowered in a fist fight by Four-Arms (albeit with support) where the classic continuity could not.
• All-Powerful Bystander: Alien X easily has the power to stop literally any threat Ben could ever face, but because his personalities are near impossible to persuade, Ben is forced to watch helplessly no matter how much chaos is unfolding before him. Bellicus and Serena's Bystander Syndrome is so much so that they treat even the destruction of the entire universe with little more than indifference and mild pity, respectively. Bellicus then treats the restoration of the universe as little more than a small inconvenience.
  Bellicus: Fine. But next time the universe and everything in it is destroyed, don't come crying to me!
• Ascended Extra: Given his Awesome, but Impractical status, Alien X only appeared once in Alien Force, where Ben swore not to use him again. In Ultimate Alien, he's limited to only a brief scene, though his species as a whole does get fleshed out more in the same episode. In Omniverse, he appears several times, with each appearance giving Ben greater control of him and playing a significant role in future episodes as well.
• Awesome, but Impractical: Possibly the most extreme example of the trope. Alien X can warp reality on a universal scale, meaning he is technically omnipotent. Unfortunately, because Ben can only control one of the three personalities he can't use any of that power, thus making the alien not only useless but dangerous, since Ben needs Serena's and Bellicus' accord to move or turn back to human. Because of this, he is the only alien where Ben had to develop a fail-safe on the Ultimatrix to ensure he wouldn't turn into Alien X.
• Berserk Button: Thanks to a Noodle Incident, Paradox is a Berserk Button for the entire Celestialsapien race. Killing him for an apparent violation of their restraining order against him is the one thing Serena and Bellicus will immediately agree to do.
• Blue-and-Orange Morality: Bellicus and Serena are so higher than mortal life that they treat the end of the universe as an inconvenience and need to have lengthy debates to determine the right action.
• Celestial Body: He seems to be a living anthropomorphic galaxy.
• Chekhov's Gunman: Because Ben swore to never turn into him again, Alien X didn't play any real role in Alien Force besides his debut (a joke from an early Ultimate Alien episode even suggests the episode was filler). He finally returns in "The Forge of Creation," where it's revealed Aggregor is planning to absorb the powers of his species and become omnipotent.
• Discard and Draw: How, ultimately, the reboot incarnation of Alien X comes off compared to his classical counterpart. Alien X does not have the ludicrous limitations that his canon self does, but in turn he doesn't have the same overwhelming power. Of course when it takes six other Omnitrix aliens fighting in tandem to take you down (and powerful ones at that, like Heatblast, Chromastone, Four Arms, AmpFibian, Ripjaws and Bloxx), the diminished power for much greater control is hardly going to be a typical problem you'd face.
• Freudian Trio: Serena is the Superego, Bellicus is the Id, and Ben is the Ego.
• Godzilla Threshold: Because of the severe drawbacks to using him and the risk of the power falling into the wrong hands, Ben only relies on Alien X if and only if there is no option but to resort to him. He first attempts to use him as a last-ditch effort to stop Aggregor in Ultimate Alien, only to fail due to Bellicus and Serena's bickering. By the Time War, Ben seems to have finally moved past that when he gets Bellicus and Serena to fall in line.
• Infinity -1 Sword: Diluted or a fraction of Alien X's powers or DNA isn't as powerful as the whole thing, but is much easier to use and is still incredibly strong. Methods this has been accessed were either through Biomnitrix fusions or Skurd.
• Informed Flaw: Word of God is that even after "Universe vs. Tennyson" Ben still has to get control from Serena and Bellicus every time he transforms and they still may limit what Alien X is able to do. However the very next episode showed Ben using Alien X with much less effort than the previous appearances and is even lampshaded by Rook saying "Ben has control over Alien X".
• Lantern Jaw of Justice: His chin is very pronounced in Omniverse.
• Like an Old Married Couple: Bellicus and Serena's relationship fits this to a T, albeit on a cosmic godly level. Their entire dynamic is based around around the fact that they can never agree on anything, but they evidently do care about each other quite a bit — Bellicus gets angry at Ben in his debut for hurting Serena's feelings, and is clearly embarrassed when she speaks to to him in a sing-song voice.
• The Load: Alien X is a reality-bending Super Mode alien, the most powerful being in the universe. The problem is that Ben has to get a majority agreement on the tasks at hand with two other personalities within the alien. But seeing as they can't agree on anything, and are only slightly more likely to agree with Ben, the form was complete dead weight until Ben had managed to convince Bellicus and Serena that he didn't need to interfere in their debates.
• Many-Faced Divinity: The omnipotent Alien X has three aspects within himself, with two of the aspects represented as floating masks.
• New Powers as the Plot Demands: He gets new powers with each appearance. Justified once being Reality Warper means you can do anything.
• Nice Mean And In Between: Of Alien X's three personalities, Serena is the voice of love and compassion (nice), Bellicus is the voice of rage and aggression (mean), and Ben is the voice of reason (in-between).
• Nigh-Invulnerable: Alien X is impervious to everything it has been hit with, ranging from blaster fire to the complete annihilation of the universe completely by virtue of deciding whether they'd be harmed. Simply put, if Ben and the other personalities agree that they don't want to be hurt, they won't be, with only other Celestialsapiens able to hurt them. However, there's one exception — they cannot survive on Anur Vladias, a Dark World where nothing survives, not even Celestialsapiens.
• Not So Invincible After All: Though Alien X is portrayed as an omnipotent being, there are certain instances where this is simply not the case. For example, he nearly loses to the Galactic Gladiator (though this is entirely justified as the gladiator is a Celestialsapien himself). Word of God also says that a lone Celestialsapien can't survive on Anur Vladias (though a group may be able to if they work together).
• Our Giants Are Bigger: Alien X is the size of a normal human; true Celestiansapiens measure in the thousands of feet tall; Kevin was easily able to crash land on one and still had acres of room to spare. However, being reality warpers, their form can easily go either way on a whim.
• Outside-Context Problem: Celestialsapiens come from outside the universe. The 5th-dimensional creators of the universe, the Contumelia, believe that the extradimensional Containment Field around the Annihilargh is impossible to breach, but Ben is able to cut through it by having Skurd morph a sword with Alien X's DNA. The Contumelia find this "interesting".
• The Power of Creation: Used this to recreate the universe after it's been destroyed.
• Reality Warper: More Reality Maker. However, Celestialsapiens have laws that dictate what can be done with their powers and when.
• Retcon: In Alien Force, Ben functioned as the tiebreaker for Alien X. If he could get either Serena or Bellicus to agree to anything then it would be decided. In Omniverse the decision had to be unanimous, with both Serena and Bellicus agreeing. This is somewhat justified, though, as the last time he got what he wanted done, they got in trouble for it. It makes sense that they'd be a little more cautious, or maybe it's even a punishment from the council that judged them.
• Retconjuration: It turns out Celestialsapiens can invoke this as a power for reality at large, which is used as a sly Hand Wave for the many Broad Strokes different teams have chosen to take with their own visions of Ben 10. Celestialsapiens are revealed in "Universe vs Tennyson" to be responsible for all the Art Shift changes and voices of characters changing, as demonstrated with Azmuth's repeatedly altered appearance and voice.
• Running Gag: Omniverse uses him as one, playing on Rook's skepticism about his existence and Ben insisting that Alien X is real while being unable to prove it for obvious reasons. Eventually, he actually does prove it to him when the destruction of the universe is triggered, forcing Ben to use Alien X. Technically, he failed to save the universe, but, being Alien X, he's able to completely reform it as though nothing had happened. Ironically, no one other than Ben has any memory of this taking place until another Celestialsapien gets onto him for it in "Universe vs Tennyson".
• Sealed Evil in a Duel: Or more accurately "Sealed Neutral in a Debate". Serena and Bellicus do not care about whatever problem Ben is having. Even the destruction of the universe itself was met with indifference. Ben had to convince them to recreate the universe because he couldn't convince them to save it in time. Ben later gets them to give him control over Alien X by suggesting that, with him in control, he wouldn't ever need to interfere with their debates.
• Sealed Good in a Can: Ben had the alien locked in the Ultimatrix so that it can only be activated for emergencies, and so Albedo couldn't access it were he ever to get his hands on a Codon receiver again.
• Self-Duplication: Can duplicate himself, because of his Reality Warper powers.
• Split Personality: An example of where this isn't good vs evil, but "war vs peace" or "love vs hate", with it being The Voice of Love and Compassion vs The Voice of Rage, with The Voice of Reason being stuck in the middle to mediate themm. All Celestialsapiens have this but how much they're in control of it varies between species.
• Split-Personality Takeover: Bellicus and Serena's influence over Alien X is so extreme that Ben had to manually lock the form from the Ultimatrix with Gwen and Kevin's help, just so that he doesn't accidentally transform into him under any circumstances. Bear in mind that not even Ghostfreak was subject to such a failsafe.
• Shapeshifting: In "Universe vs. Tennyson", he is able to shapeshift into a galaxy shaped thing that has enough of a gravitational pull that it sucks in the Galactic Gladiator... who had itself grown to the larger than a planet.
• Sizeshifter: Celestialsapiens in general are positively massive, being larger than planets or even entire galaxies when seen in "The Forge of Creation". However, Alien X himself is about the size of an average human.
• Story-Breaker Power: If not for the whole Awesome, but Impractical aspect, Ben could be invincible just by using this form all the time. After Ben gets complete control over the form in "Universe vs Tennyson", the only limit other than random chance is Ben's own imagination. Just to show it off, Ben beat the combined force of the Rooters and the brainwashed Amalgam kids simply by making them shoot each other. However, he still has to be careful with how he can use his powers or he will get in trouble again.
• Telekinesis: It's part of Alien X's powers, but never used until he fights the Rooters and makes them fight each other.
• Time Abyss: Celestialsapiens are extremely long lived beings. Bellicus at one point implies that he and Serena have existed since the age of Dinosaurs.
• World's Strongest Man: Alien X is by far the strongest alien in the Omnitrix, by virtue of being a Reality Warper. Though despite his insurmountable godlike power, he is Awesome, but Impractical.
• "X" Makes Anything Cool: The X in his name highlights the mysterious nature of his Reality Warper powers. It also doubles as a Stealth Pun, as X is the Roman numeral for 10, and he's the tenth alien introduced in Alien Force.
• Voice of the Legion: When he does speak, it's Bellicus, Serena, and Ben in unison.

Big Chill

Big Chill/Ultimate Big Chill (AF-04, UA-03)

^{Click here to see Ultimate Big Chill}

Voiced by Dee Bradley Baker

Big Chill was sampled from a Necrofriggian from planet Kylmyys. An ice planet full of large glaciers and ravaged by snowstorms, Kylmyys was for a long time thought to be uninhabited, as any life form on it would be instantly frozen. However, Necrofriggians were able to evolve in the deep caves, developing an ability to turn intangible so they could resist extreme climates, as well as ice-based powers. Due to this ability, they were also able to colonize other similarly uninhabitable worlds, such as planet Mykdl'dy.

Necrofriggians are also an asexual species that reproduce every 80 years by laying eggs.

Ben 23's version is named Freezeghost.

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• Art Evolution: He goes from his skeletal appearance in Alien Force/Ultimate Alien to huge and bulky in Omniverse.
• Batman Can Breathe in Space: Young Necrofriggians live in space and feed on solar plasma.
• Big Creepy-Crawlies: He looks like a giant, vaguely humanoid, skeleton-like moth. Even more so in Ben 10: Omniverse, where the skeleton aspect is dropped in favor of making him look more like a bulky bug.
• Bizarre Alien Sexes: Necrofriggians appear to be a One-Gender Race, as Big Chill laid eggs even though Ben's alien forms are usually male. When asked if Big Chill was a female, Dwayne McDuffie replied "sort of".
• Breath Weapon: Ice breathing, to be accurate.
• Combo Platter Powers: He has Ghostfreak's intangibility mixed with Arctiguana's ice powers.
• Creepy Good: Not as much as Ghostfreak, but he still comes up as creepy, with his skull-like face and ghostly voice.
• Elemental Rock-Paper-Scissors: Averted. Big Chill can withstand extreme cold and extreme heat, hailing from a planet that has both. Not even drinking molten steel is a problem.
• Evolution Power-Up: Downplayed. Like Cannonbolt, Big Chill's current state is powerful enough to a point where evolution has a minimal effect. When "changing" into Ultimate Big Chill, the only alterations to be had appearance-wise are a palette change and some flame accents. Changes to Ultimate Big Chill's powers simply include taking longer breaths, creating ice out of thin air, and being able to flash-freeze almost anything.
• Extreme Omnivore: When in Mister Seahorse mode, Big Chill's species chomp down on anything metal and regurgitate it to create a nest for their children. This even gets to the point where Big Chill can digest molten steel without any ill side effects!
• Fauxshadow: One episode has him going out of Ben's control, and Gwen believes that he's following in the footsteps of Ghostfreak since they're both ghost-like aliens. But actually, no, Big Chill was just getting ready to be a mommy/daddy/whatever.
• Flying Firepower: A flyer with powerful ice breath abilities.
• Foil: To Heatblast. Both are flying elemental aliens yet are not Ben's primary fliers in their respective sets (the role is instead given to Stinkfly in the original series and Jetray in Alien Force). However, Big Chill's main power is his cryokinesis while Heatblast is on the complete other end of the spectrum. Heatblast is durable enough to be thrown through buildings while Big Chill has to rely on his maneuverability and intangibility to merely stay in the fight.
• Ghostly Chill: The inspiration for his powers. Naturally, Big Chill himself takes it up a notch — when he passes through someone, he can freeze them solid.
• Glass Cannon: His ice powers are extremely powerful and able to defeat much stronger opponents, but his physical structure is relatively weak compared to most of Ben's fight-oriented aliens, making him easy to defeat if you find a way to attack him before he goes intangible (good luck with that, though).
• Grand Theft Me: At one point, Big Chill's subconscious takes over Ben's body, similarly to how Ghostfreak did in the original series, but it wasn't for evil intentions — it was to give BIRTH.
• Harmless Freezing: As per usual for a kids' action cartoon, Big Chill's ice is like this. All the enemies he freezes eventually thaw out and are perfectly fine in later episodes.
• An Ice Person: Though he's primarily used for his ice breath, Big Chill has several methods of freezing opponents including shooting ice beams from his hands, through physical contact, and by going intangible. Big Chill also has the ability to freeze the water in the air to create ice constructs and his cryokinesis has successfully overpowered fire attacks more than once.
• Intangible Man: And can freeze everything he phases through to boot.
• In the Hood: When folded, his wings form like a natural cape and hood, giving him a Grim Reaper-esque look.
• Light Is Not Good: Albedo as Big Chill in Omniverse has a paler color scheme, compared to Ben as Big Chill.
• Mama Bear: Pregnant Necrofriggians get very aggressive when they believe their eggs are threatened.
• Mister Seahorse: Big Chill's species reproduces asexually every 80 years by laying eggs. Ben is no exception, to the point the form's instincts actually took over his human form to force him to turn into Big Chill regularly and prepare it.
• The Mothman: Explicitly modeled off this alleged cryptid.
• Our Ghosts Are Different: In this case, this ghost is an ice-breathing alien bug.
• Pungeon Master: Big Chill loves to make ice puns.
• Shout-Out:
  • He is based on the alleged real life cryptid known as "the Mothman".
  • His Omniverse design is reminiscent of Batman's outfit from Batman: The Brave and the Bold, while his overall build takes after Man-Bat.
• Split-Personality Takeover: When Big Chill is pregnant, Ben can only transform into him, and focuses primarily on eating any metal it can find and isolating itself away from external conflict (and attacking those that intrude on his territory). When Ben reverts back to normal the next day (or after he's given birth), he has no memory what happened the night before. That said, once he's actually given birth, Big Chill never takes over Ben's mind/body again, making him a very downplayed example compared to Ghostfreak or Alien X.
• The Stoic: He rarely emotes, to the point he only smiled twice in Alien Force.
• Super Not-Drowning Skills: The Ultimate Alien episode “Deep” shows him breathing and using his powers just fine underwater.
• Super-Strength: He is capable of easily ripping metal statues and steel girders apart.
• Technicolor Fire: Reversed. Big Chill blows blue ice breath, while Ultimate Big Chill breathes red "ice flames" that create an instant ice sheet glaciers.

Brainstorm

Brainstorm (AF-07)

Voiced by Dee Bradley Baker (Alien Force, Ultimate Alien), Corey Burton (Omniverse)

Brainstorm was sampled from a Cerebrocrustacean, a species of sentient, highly intelligent crabs from planet Encephalonus IV. This planet being a place with a lot of energy problems, its inhabitants have developed the ability to produce electrical energy of their own from their very brain. Cerebrocrustaceans are the second smartest species in the galaxy, preceded only by Galvans.

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• Awesomeness by Analysis: In "The Vengers", he curb-stomps the Vengers by predicting their tactics, taking advantage of their weaknesses, and using the environment against them.
• Demoted to Extra: Ben only uses Brainstorm three times in Omniverse, one of which was to be dunked in a dunk tank and the final was a cameo with the rest of his aliens in the finale. He's even absent from "Max's Monster," an episode where Phil had forced the Omnitrix to only transform Ben into electrical aliens — in fact, Brainstorm is the only one that doesn't appear there. Apparently, this was due to Brainstorm's low toy sales; instead, Doctor Psychobos, a fellow member of his species, was partially created to make up for this.
• Divergent Character Evolution: Omniverse makes him more of an offensive alien, being able to analyze the environments and enemies, and then use them to his advantage, making him more different from Grey Matter, whose strengths are more in technology and infiltration.
• Dr. Brainpart: Like Grey Matter, his name references his superior brain. And the fact he can create electric shocks.
• Genius Ditz: Ben's most intelligent alien during Alien Force/Ultimate Alien and second most intelligent species in the galaxy. That said, Ben often gets distracted and makes foolish decisions while in this form. Averted in Omniverse, however, where he was shown more capable.
• Giant Enemy Crab: Not that big, seeing how he is around the size of a human, but that's still giant compared to a regular crab.
• Head Blast: Brainstorm can open up the exoskeleton plates on his skull to fire electric bolts from his brain.
• Improbably High I.Q.: In "The Vengers", his Inner Monologue displayed his IQ as 10^30.
• Insufferable Genius: In Alien Force and Ultimate Alien, Ben becomes distinctly more arrogant in this form and frequently boasts about his intelligence. This is done away with in Omniverse.
• Mighty Glacier: As a crab, he cannot move very quickly, but he compensates by producing powerful electrical attacks and forcefields.
• My Brain Is Big: It's not hard to see where his genius comes from — his brain is absolutely massive.
• Power Floats: He is capable of levitation, though he tends to prefer scuttling along the ground.
• The Rival: Apparently, Galvans and Cerebrocrustaceans tend to have a rivalry over which one of them is the smartest species in the Universe; Cerebrocrustacean villain Dr. Psychobos' entire motivations revolve around proving his species is superior to the Galvans, Brainstorm once had a small argument on the subject with Azmuth, and Galvan minor characters Blukic and Driba have been known to make condescending comments about Cerebrocrustaceans at least twice in the show.
• Sesquipedalian Loquaciousness: Cerebrocrustaceans as a whole seem to instinctively express themselves that way, and Brainstorm is no exception. This actually sometimes becomes a weakness, as he can distract himself during fights.
• Starfish Aliens: Giant crab-like aliens with oversized heads, and shell capable of exposing their brains.
• Smart People Speak the Queen's English: Why else would he have a British Accent?
• Shock and Awe: His brain can generate electric attacks and forcefields by mere thought.
• Super-Intelligence: See Improbably High I.Q. above. His brain operates like a supercomputer, able to solve insanely difficult calculations in seconds and predict exactly how each of the Vengers would behave during and after battle.
• Telepathy: Cerebrocrustaceans do not speak with their mouths. Instead, they mentally project their thoughts as sound waves. This can be seen through the fact that Brainstorm doesn't open his mouth when he talks, but did when he threw up in "War of the Worlds."
• The Smart Guy: Replaced Grey Matter as this during the Alien Force/Ultimate Alien era.
• Took a Level in Badass: In Alien Force and Ultimate Alien, his intelligence was a liability in combat rather than an asset; he never used it to fight tactically and was more likely to distract himself with his musings than anything else. He pulled off a physics simulation in his head once to win at golf but had never done anything like that in the heat of combat. In Omniverse, he pulls off something akin to Sherlock Holmes (2009), effortlessly defeating his opponents through tactical use of his understanding of his opponents, his powers, and his environment.
• Wall Crawl: He can scuttle along walls as easily as the ground.
• Weak, but Skilled: Ben considers him this by Omniverse. When he brings him out for his big showcase he outright says he 'doesn't even need one of his heavy hitters', indicating that Ben doesn't consider Brainstorm one of his more powerful transformations, but using his super intelligence and strategic use of powers he wipes out an entire villain team without much effort.
• Vocal Evolution: He has a different voice and accent in Omniverse as a result of Corey Burton taking over and giving him an Austrian accent.

Chromastone

Chromastone (AF-05)

Voiced by Dee Bradley Baker (Alien Force, Ultimate Alien), Eric Bauza (Omniverse)

Chromastone was sampled from Sugilite, the Single Specimen Species guardian of Petropia before Vilgax caused its destruction. A crystal-based alien, he possesses the ability to absorb light and energy, channeling them into attacks.

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• Back for the Finale: He shows up in the final episode of Omniverse after an extended absence. He later shows up in the final episode of the reboot used by Alien Force Ben against Alien X.
• Cyclops: He has a single eye on his head.
• Crystal Dragon Jesus: "Secret of Chromastone" reveals the alien who provided the sample for Chromastone was Sugilite, the guardian of Petropia, whose role was to allow the planet and its inhabitants to be reborn after their destruction by the hand of Vilgax.
• Divergent Character Evolution: He gained the ability to fly in Alien Force's season 3, contrasting him with the returning Diamondhead. This power never appears again in Omniverse, due to largely phasing him out.
• Disney Death: Played with. Chromastone's body was destroyed by Vilgax in "Vengeance of Vilgax"; while Ben survived, his body was reformed into Diamondhead and Chromastone was seemingly lost for good. In "The Secret of Chromastone," however, Tetrax is able to revive Sugilite (Chromastone's genetic donor) from inside of Diamondhead, who tells him that Chromastone is still inside of the Omnitrix. Still, Ben continues to not use him for the remainder of Alien Force. It's finally settled in Ultimate Alien, where Ben uses him in the first episode and returns to using him regularly.
• Energy Absorption: His main power allows him to absorb any form of light or energy attack directed at him, then channel it into his own attacks.
• Flight: Gains this ability in "The Secret of Chromastone".
• Light 'em Up: Though he lacks Diamondhead's Gemstone Assault ability, he trades it for an amplified ability to absorb light and energy in general, channel it inside his body, and redirect it as light-based attacks.
• Lightning Bruiser: He seems to be faster and more agile than Diamondhead, but not as strong and durable.
• Nigh-Invulnerability: To date, Vilgax is the only one who ever managed to damage him.
• The Only One: Chromastone was sampled from Sugilite, who is the only being in the universe who can restore the dead planet, Petropia.
• Overshadowed by Awesome: His role as Ben's energy absorber is taken by Feedback in Omniverse. In fact, when Ben tries to use him to absorb the energy of Maltruant's Annihilarg, the Omnitrix shifts through his alien forms until it gives him Feedback instead.
• Put on a Bus: He only made one appearance in Omniverse near the beginning of the series, and it was just being used to test Blukic and Driba's new weapon. He didn't show up again until the finale. Word of God is that this was due to [1]◊ Chromastone's low toy sales.
• Retcon: His biography initially introduced him as a separate species from Diamondhead, called Crystalsapiens, with their own planet known as Motoresi. This was retconned as a legend after "The Secret of Chromastone" revealed he actually was from the same planet as Diamondhead.
• Rock Monster: Just like Diamondhead. His species is even from the same planet as him.
• Shipless Faster-Than-Light Travel: A genetic duplicate of Chromastone can fly to his homeworld from Earth within minutes.
• Single Specimen Species: Sugilite, Chromastone's genetic donor, is the only Crystalsapien in existence.
• Suspiciously Similar Substitute: To Diamondhead; albeit with more energy-based powers. "The Secret of Chromostone" reveals that these similarities are more than just coincidental, as the two species hail from the same planet. Amusingly, this is inverted in season 3 of Alien Force, where a shattered Chromastone reforms into Diamondhead to defeat Vilgax.
• Weaksauce Weakness: The pilot episode of Ultimate Alien reveals that Chromastone is incredibly weak to water, as it causes his powers to electrocute himself to the point of passing out.
• You Don't Look Like You: His first appearance in Omniverse had him looking exactly the same as he did in Alien Force and Ultimate Alien. When he returns in "A New Dawn", his design is heavily modified, incorporating several more spikes, clothing, a different face, and a new body shape, bearing a resemblance to the Shredder.

Echo Echo

Echo Echo/Ultimate Echo Echo (AF-02, UA-11)

^{Click here to see Ultimate Echo Echo}

Voiced by Dee Bradley Baker

Echo Echo was sampled from a Sonorisian from Sonorisia. Massive, majestic gorges and immense, breath-taking canyons displaying beautiful layers of multi-colored strata from their gradual formation over the ages can be found all over Sonorosia. Sonorosians are the only natives with the innate ability to manipulate sound waves, but other creatures on Sonorosia are able to take advantage of the planet's cavernous topography, utilizing different specific locations on the landscape as whisper chambers or to generate echoes as a defense mechanism. They use the immense gorges to use echolocation to find each other.

Ben 23's version is named Copy-Copy.

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• Attack Drone: Ultimate Echo Echo trades the Doppelgänger Attack for a series of floating discs that act as speakers for his sonic attacks. "Sonic Doom" is his most powerful and devastating move, which bombards an opponent with an omnidirectional sphere of ear-splitting sonic waves.
• Calling Your Attacks: He has names for several of his moves, such as "Wall of Sound" (a row of clones screaming all at once) and "Echo Chamber" (a group of clones screaming from different directions). Ultimate Echo Echo has "Sonic Doom" (a group of sonic discs surrounding the opponent in every direction and blasting them all at once).
• Combination Attack: All of his Signature Moves involve either multiple clones or sonic discs.
• Doppelgänger Attack: He uses his clones to create many powerful combo attacks.
• Evolution Power-Up: Ultimate Echo Echo is arguably Ben's most powerful Ultimate Alien (besides Way Big, of course). While losing his ability to clone himself, he obtains detachable sonic discs that come from the light-blue holes on his body that are powerful enough to contain a nuclear explosion and can replicate themselves in case Ultimate Echo Echo needs more firepower. His unique use of decibel force leaves him unrivaled, even when facing Ultimate Kevin.
• Flight: Ultimate Echo Echo gains the power to fly.
• Literal Split Personality: If several Echo Echo clones all turn back into Ben at once, the result is multiple Bens but inheriting a different part of his personality.
• Pint-Sized Powerhouse: One of the smallest aliens, but he packs a punch with his sonic scream.
• Powered Armor: Echo Echo's body seems to be either a small robot or containment suit of some kind. This can be seen not just through his appearance and voice, but the fact that when his clones are destroyed in battle, nothing appears to be inside of them.
• Robo Speak: Sounding like a speech synthesizer as Echo Echo, but loses almost all inflection and goes straight into Machine Monotone as Ultimate Echo Echo.
• Self-Duplication: Unlike Ditto, however, the duplicates are not constantly synced to each other, so it is possible for each one to transform into different forms separately, as seen in the episode "Duped" of Ultimate Alien. Ben exploits this advantage by being sure to hide one clone just in case all the other copies get killed. Ultimate Echo Echo does not have this power, at least on his own; instead, his discs are the ones that duplicate.
• The Stoic: Ultimate Echo Echo's voice is very deep and subdued compared to the shrill and screechy Echo Echo, indicating a huge change in power and disposition.
• Story-Breaker Power: Both regular and Ultimate Echo Echo fit this to a certain degree. Ultimate Echo Echo's Sonic Doom has single-handedly defeated almost every opponent it's hit, up to and including Ultimate Kevin. Even with normal Echo Echo, though, his ability to duplicate with no drawbacks makes it extremely difficult to fully take him down. He even keeps a spare clone in his car just in case the others are somehow defeated.
• Super-Scream: Sonic screams are his basic form of attack.
• Suspiciously Similar Substitute: To Ditto, being a small alien capable of duplicating, but with the added benefit that Echo Echo clones can die without harming the others.

Goop

Goop (AF-09, RE-167-172)

Voiced by Dee Bradley Baker

Goop was sampled from a Polymorph from Viscosia. A volcanic planet with a significantly lighter gravity than Earth, molten magma flows freely on Viscosia, constantly shaping and reshaping the jagged planetary surface in its path. Lava weeps out from fissures in the ever-changing landscape. Polymorphs are unicellular organisms capable of shaping themselves as they want and float on the planet's lighter gravity.

Ben 23's version is named Muck-O-Muck.

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• Acid Attack: He can turn himself into living acid.
• Blob Monster: He is made of a slimy, liquid substance that requires a UFO-shaped anti-gravity device to move and keep himself together. As a result, he can alter his shape and fly as long as the device isn't damaged or shut down.
• Boring, but Practical: Compared to the other starter aliens Ben has at his disposal in Alien Force, Goop seems like a generic, relatively underwhelming Blob Monster by comparison. However, his acidic properties are capable of burning through tough materials, and his body is capable of twisting and contorting into pretty much anything without issue.
• Confusion Fu: His lack of anatomy means he could throw a punch from any part of his body if he so chose.
• Covered in Gunge: Not him, but others when he takes a hit.
• Good Colors, Evil Colors: Aside from the eyes and Ultimatrix symbol, in Omniverse, Albedo's Goop has a red body and Anti-Gravity Projector, in contrast to Ben's green.
• Goo It Up: This is his primary powerset, as part of being a Blob Monster.
• Lightworlder: Polymorphs' homeplanet has much lighter gravity than Earth. This is the reason Goop needs the anti-gravity device to move.
• Nigh-Invulnerability: By way of being made of fluids. (See Blob Monster)
• Tastes Like Chicken: According to Word of God, Goop has flavors. Ben is lime-flavored, Albedo is raspberry, Ben 23 is blueberry, Bad Ben is licorice, Mad Ben is sour orange, Nega Ben is black pepper, and Benzarro is grape.
• Voluntary Shapeshifting: To a point. He can flow through any opening his little saucer can get through.
• Weaksauce Weakness: Take away his saucer, and he's immobilized. Ben uses this to get the Omnitrix back from Vilgax on Primus.

Humungousaur

Humungousaur/Ultimate Humungousaur (AF-02, UA-06 ^note Although he was used by Albedo in AF-45, RE-82)

^{Click here to see Ultimate Humungousaur}

^{Click here to see Ultimate Humungousaur as used by Albedo in Omniverse}

Voiced by Dee Bradley Baker (Alien Force, Ultimate Alien), John DiMaggio (Omniverse), David Kaye (Reboot)

Humungousaur was sampled from a Vauxausaurian from planet Terradino. A beautiful, mountainous, and lush world, Terradino is home to a vast and varied number of diverse animalistic alien species, many creatures great and small. Tragically, all these different species have not evolved to live here together peacefully. Warring factions in every group constantly seek to wrench control of society for themselves. However, the Vaxasaurians have been able to temporarily restore order through their sheer physical superiority.

Ben 23's version is named Dino-Mighty.

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• Adaptational Wimp: Humungousaur cannot change his size in the reboot.
• Appropriated Appellation: In the reboot series, he is given his name by a little girl bystander.
• Atrocious Alias: It's a good thing a little girl suggested his name in the reboot because Ben's ideas were "Gigantigecko", "Iguana Monster", "Roar Thing" and "Mega-Stega Dude".
• Attack of the 50-Foot Whatever: Not as tall as Way Big, but his regular size still goes around a Tyrannosaurus rex, and he can grow again to 60 feet.
• The Big Guy: He serves as the replacement for Four Arms in Alien Force. After Four Arms is brought back, both fill the role together.
• Boring, but Practical: Yeah, he doesn't do much other than change size and hit his enemies super hard, but in fairness Ben doesn't need much else from a dinosaur-like alien like him.
• Composite Character: The reboot incarnation incorporates the spiked tail from Ultimate Humungousaur.
• Destructive Savior: Downplayed — he's much more controled than Four Arms, but still causes some destruction here and there, by accident of course.
• Divergent Character Evolution: Zig-Zagged. Humungousaur originally was able to change his size, but this power gradually stopped appearing, which made him just another alien with Super-Strength. The reboot, however, gives him a spiked tail similar to Ultimate Humungousaur's, and it has the ability to send out shockwaves, which makes him a bit more distinct from Four Arms.
• Epic Flail: Ultimate Humungusaur has a club-tail like an Ankylosaur, only his has a mace-like spiked ball.
• Forgot About His Powers: About midway through Ultimate Alien, he inexplicably stopped using his power to grow. By extension, his ability to develop armor on his body disappears as well.
• Evolution Power-Up: In his ultimate state, Humungousaur loses his ability to grow, instead being fixed at his largest optimal size. He also becomes stronger, heavier, and gains Gatling gun knuckles that shoot regenerating bone rockets.
• Inconsistent Spelling: Word of God says that his name was originally spelled Humungosaur, and the extra "u" was a typo that stuck, much to Dwayne's displeasure.
• Lightning Bruiser: He's pretty agile for his size, and has been shown doing somersaults and flips.
• Sizeshifter: He was initially introduced as capable of growing to 60 feet with additional strength as a result. Then the writers apparently forgot he could do that, and he hasn't done it since "Eye of the Beholder". He lacks this power in the reboot.
• More Dakka: Ultimate Humungousaur can turn his hands into four-barrel rocket launchers.
• Not Zilla: As close to this trope as one of Ben's aliens can get, especially when he grows to his full size. He doesn't have a Breath Weapon, though.
• One-Man Army: He is one of the best aliens to take on multiple aliens. In Omniverse, he was able to take on a large portion of Ben's rogue gallery all at once.
• Prehistoric Animal Analogue: The only dinosaur-like alien of the Alien Force era, and he becomes even more dinosaur-like as Ultimate Humungousaur.
• Sizeshifter: He can grow much larger, adapting spikes on his back when he does so. Sadly, somewhere between the seasons, he stops doing so, possibly in favor of Way Big.
• Shockwave Stomp: In the Reboot, hitting something hard enough with his armored tail creates a powerful sonic attack.
• Super-Strength: Sure, his size should give him away. But even then considering he can raise a house on his own, and can throw objects well past orbit...
• Super-Toughness: Took lasers and missiles directly and only staggered.
• Spotlight-Stealing Squad: The most frequently used alien in Alien Force (after Jetray) and Ultimate Alien, and the most frequently used for combat. Whenever there's an uncertain enemy, Ben will most likely reach for Humungousaur. It's averted in the first two seasons of Omniverse, whereas part of a Running Gag each time Ben tries to select Humungousaur, the Omnitrix gives him something else.
• Suspiciously Similar Substitute: To Four Arms in Alien Force and Ultimate Alien, as both are the large strength aliens.
• Underwear of Power: He wears a pair of black briefs in Omniverse.
• The Worf Effect: In Alien Force, Albedo as Ultimate Humungousaur curbstomped Ben as Humungousaur. In Omniverse, Ben easily defeats Negative Ultimate Humungousaur as Feedback.
• Top-Heavy Guy: His torso is enormous and his arms very lengthy, reaching his knees. By comparison, his legs are about a third of the size of his arms.
• Your Size May Vary: Even after Humungousaur stopped using his Sizeshifter abilities, he still hasn't been shown at a consistent size. While he never nears the skyscraper size he originally had, he ranges from only a head or two taller than the humans to bigger than a small house.

Jetray

Jetray (AF-03, RE-134)

Voiced by Dee Bradley Baker

Jetray was sampled from an Aerophibian from planer Aeropela. An oceanic planet completely covered in water with giant spiral rocks protruding out of the sea, Aeropela is constantly visited by fog, rain, and hurricanes, as well as the occasional monsoon or tsunami. Aerophibians have evolved to fly, swim and survive in this harsh climate, building their cities inside the planet's spiral rocks. In prehistoric times, their primitive ancestors used their abilities to shoot neuroshock blasts to paralyze and catch their prey. Nowadays, they still possess this ability, but use it more for self-defense.

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• Batman Can Breathe in Space: Jetray can survive in and travel through space. Apparently, this is a major reason he was introduced in the reboot.
• Beware My Stinger Tail: His tail can shoot neuroshocks. This has caught numerous opponents off guard trying to counter his Eye Beams.
• Boring, but Practical: Jetray is tied with Cannonbolt as being one of Ben's most used alien forms. Possessing super speed not affected by water, the ability to fly, AND shoot energy blasts makes him very, very versatile. It's to the point the writers actively had to sideline him in Omniverse because they realized just how much Ben actively fell back on him during Alien Force and Ultimate Alien.
• The Bus Came Back: Despite being sidelined in Omniverse, Jetray makes a return to active use in Season 4 of the reboot.
• Contrasting Replacement Character: He replaces XLR8 as the primary means of transport during the Alien Force/Ultimate Alien era, though their power sets are quite different. XLR8 is great for land travel and useful for melee combat, while Jetray is used for air travel and ranged combat with his neuroshocks.
• Eye Beams: He can shoot powerful beams called neuroshocks from his eyes (and tail).
• Flight: Replaced Stinkfly in the Alien Force era, and later in Season 4 of the reboot, as Ben's main flyer.
• Flying Firepower: Can fly at high speed. Can also shoot neuroshock blasts from his eyes and tail.
• Flying Seafood Special: An alien based on an aquatic earth creature (manta rays) that can fly.
• Fragile Speedster: Ben's fastest alien in Alien Force era and remains one of the fastest period, behind XLR8 and Fasttrack. However, he isn't very tough and goes down quite easily if he gets hit.
• How Do I Shot Web?: Reboot Ben has a hard learning curve in mastering his flight powers in comparison to Stinkfly.
• Informed Ability: According to his official profile, he can breathe underwater; this was never shown (the only times we see him underwater, he quickly gets out of it; except in the Alien Force video game, which has an underwater sequence that Ben must traverse as this alien).^note This also fits under If It Swims, It Flies.
• Put on a Bus: He's one of four aliens to not appear in Omniverse, primarily because he was overused in the previous two shows.
• Shipless Faster-Than-Light Travel: In one episode, Jetray enters hyperspace and flies halfway across the galaxy in just a few seconds.
• Shout-Out: His abilities are exactly like Zok from the Herculoids.
• Super-Speed: Whether in the skies or underwater, Jetray can fly incredibly fast. There's a reason why he used to be one of Ben's main aliens for transportation.
• Suspiciously Similar Substitute: Jetray is practically one to Ripjaws as the main aquatic alien in Alien Force.

Lodestar

Lodestar (AF-31)

Voiced by Dee Bradley Baker

Lodestar was sampled from a Biosorvotian from an unknown planet. He has powerful magnetic abilities.

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• Barrier Warrior: He can create a magnetic barrier in front of him that repels all metallic objects.
• Demoted to Extra: He only made three appearances in Omniverse. Somewhat excusable due to Gravattack, whose mastery over physics pretty much makes him more useful than Lodestar.
• Early-Bird Cameo: In the Alien Force season 2 finale with Ben discovering his hologram.
• From a Single Cell: He can regenerate from even a single sliver of his body, a power revealed in the aftermath of his body being completely blown apart.
• Floating Limbs: His head floats above his body via magnetism (it can even be knocked away and come right back).
• Flight: He can use his magnetic powers on himself to fly.
• Invisible Anatomy: His head seems to be nothing more than a metal ball held up by a magnetic field, but his body comes along if it's moved.
• Losing Your Head: Lodestar's head can be knocked away from his body by a powerful enough force, resulting in some humorous moments where the body aimlessly wanders around for it (with the head itself trying to direct it).
• Magnetism Manipulation: His main gimmick is harnessing magnetism to control metal.
• Overshadowed by Awesome: While there aren't too many aliens Ben has at his disposal that can manipulate metal, the fact that Lodestar is so situational means that there's plenty of other aliens that tend to be used in his stead.
• Pulling Themselves Together: Does it when he gets blown up in "Ultimate Aggregor".
• Robo Speak: Like Echo Echo, he has a synthesizer-voice.
• Selective Magnetism: His main power. His magnetic rays can either lift metal objects like telekinesis or attract metal objects toward a specified opponent.
• This Looks Like a Job for Aquaman: Due to his power set, Lodestar is next to useless if there's no metallic substances around him, limiting his usefulness to fighting robots or similarly metallic beings. As such, he's one of Ben's lesser used aliens.

Nanomech

Nanomech (Alien Swarm)

Voiced by Alex Winter (Alien Swarm), Dee Bradley Baker (Ultimate Alien, Omniverse)

Introduced in the movie Ben 10: Alien Swarm, Nanomech was sampled from the Hive, a species of nanomechanical parasite life forms that intended to rule over Earth then. Due to some weird result of the DNA combination, Nanomech retains some human features compared to his natural species' usual state. A living nanorobot, he is incredibly small and can shrink even further.

Ben 23's version is named Teeny-Weeny.

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• Curb-Stomp Battle: An extremely ironic one: Ben's Nanomech easily defeated Mad Ben's Way Big by flying inside his head and shooting his brain until he fell over.
• Cyber Cyclops: Yet another of Ben's one-eyed aliens.
• Flying Firepower: A rather weak one, but he can still fly and shoot electrical attacks.
• Half-Human Hybrid: Compared to the original version of the species he was sampled from, Nanomech possesses more humanoid features. This actually makes him stronger than a regular drone of his species.
• Helium Speech: For Ultimate Alien, to go with his microscopic stature. Although this only applies to people larger than he is (Ie humans) to other creatures Nanomech's size his voice is relatively deep.
• Hive Mind: In Alien Swarm, turning into Nanomech made him hear the voice of the Queen. Luckily, he resisted.
• Joke Character: He's Ben's smallest, and by extension frailest alien, which leads to a number of humiliating defeats. Examples include being crushed inside of a book, and in another episode hit by a flyswatter.
• Lethal Joke Character: Much like Grey Matter, he is small and possesses weak attacks, but he can be used to destroy robots from the inside. Not to mention his size and abilities actually make him the perfect opponent to defeat a To'kustar.
• Mechanical Lifeforms: Based on a species of nanomachines.
• Shock and Awe: Nanomech can unleash a powerful electrical attack.
• Silicon-Based Life: Kevin describes the nanomachines as such in Alien Swarm.
• Sizeshifter: Nanomech starts at about an inch, and can shrink so much smaller that he could maneuver between the lava droplets of an eruption.
• Winged Humanoid: He has four bug-like wings. The show forgot the first time for no apparent reason, but they remembered later.

Rath

Rath/Ultimate Rath (AF-39, RE-84)

LEMME TELL YA SOMETHING, TROPER WHO IS READING THIS PAGE RIGHT NOW...

^{Click here to see Ultimate Rath as used by Albedo}

Voiced by John DiMaggio (Alien Force to Omniverse), Dee Bradley Baker (Reboot), Bill Rogers (Power Trip)

Rath's DNA was sampled from an Appoplexian from Appoplexia. A species of sentient, anthropomorphic tiger-like beings, Appoplexians are Hot-Blooded, aggressive, short-tempered and not very smart, believing you can solve any problem by hitting it (Or, sometimes, just by "hitting things a lot"). They do, however, possess high durability, as well as ridiculous strength and reflexes.

Ben 23's version is named Tigerizer.^*According to Derrick J. Wyatt’s Twitter

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• Absurdly Sharp Blade: He can cut an entire giant rock in two with just one of his claws.
• Actor Allusion: This isn't John DiMaggio's first time voicing an anthropomorpic tiger.
• And This Is for...: He does this while fighting Poltroon in "Food Around the Corner", putting him on the receiving end of a few wrestling moves.
  Rath: (grabs Poltroon’s arm) This is for trying to blow up my people! (throws him a good ways down the hall) This is for trying to blow up your people! (jumps at him, giving him a knee to the chest, then grabs him by the shoulders) AND THIS IS FOR TRYING TO BLOW UP ME!
• Badass Boast: His "Lemme tell ya something" speeches are intended to be this. It usually ends up more like parodying it, but on occasions, he can actually give quite awesome ones; the one he delivered to Jarett of the Pantophage was particularly epic.
  Rath: Lemme tell ya something, Jarett of Pantophage! I just jumped down your throat! You start a war with the Lewodans, and I will do it again, only this time, I will knit your intestines into a sweater!
• Berserk Button:
  • Ruining his food is a surefire way to make him mad.
    "You can hurt me. You can hurt the things I stand for! You could even hurt my feelings, if I had any! But nobody, and I mean NOBODY, hurts the smoothie!"
  • He also doesn't like to be called a "kitty".
• The Big Guy: Right behind the likes of Four Arms, Humungousaur and Way Big in terms of sheer brute strength, but with the added benefit of agility and Wolverine Claws.
• Blood Knight: He loves violence, and his Hair-Trigger Temper means he won't hesitate to jump into a fight.
• Boisterous Bruiser: Every line out of his mouth is in the style of a pro wrestler.
• Breakout Character: Ever since Rath was unlocked in Alien Force, he quickly became very well-liked and is one of Ben's most used alien forms. He was also the first Alien Force alien to make the transition to the reboot, with Dr. Animo briefly becoming Rath in Season 2, before Ben fully unlocks him in Season 3.
• Calling Your Attacks: In the form of Constellation/Star + wrestling move = "Polaris Pile Driver!"
• Cats Hate Water: Omniverse increased his catness, and thus gained a dislike of water.
• Destructive Savior: In spades. His clumsiness and violent behavior often result in property damage.
• Does This Remind You of Anything?: Rath raising his singular Wolverine Claws while making his Badass Boast occasionally comes off looking like he's Flipping the Bird instead.
• Dumb Muscle: The only one of Ben's physically strong aliens (up to that point in the series) to be this. Whereas all other aliens can be destructive but are fully controlled, Rath is the only transformation where Ben gets dumber and much more aggressive, making it one of his least controllable forms. However, since he usually uses it for heavy combat, he doesn't really mind.
• Evolution Power-Up: In the Ultimatrix simulations, the rage of Ultimate Rath's ancestors is downplayed to prolong his survival and he is less impulsive thusly. He also becomes bigger, stronger, meaner, and cooler of all things. He gains additional claws not only on his knuckles, but also on his fingers, toes, and elbows, plus three spikes on his hunched back.
• Exposed Extraterrestrials: In the Omniverse episode "Food Around the Corner", it’s revealed he’s this even by his own species’ standards, as it turns out despite their loud and aggressive demeanor, Appoplexians have an advanced sense of shame.
• Flanderization: Omniverse flanderizes his cat-like aspects via making him afraid of water (even though tigers have no problem with water), distracted by string-like objects and laser pointers, and vulnerable to Nyancy Chan's cat control powers (even though Rook, who is also a cat-like alien, couldn't be controlled).
• Full-Frontal Assault: Ben was not happy to find out that members of Rath's species normally wear clothes.
• Full-Name Basis: Addresses everyone by their full name and title most if not all of the time, most prominently during his "Lemme tell ya something..." speeches.
• Hair-Trigger Temper: This is a genetic trait amongst Appoplexians. Good luck finding anything that doesn't make Rath mad.
• Horrifying the Horror: The Vreedle Brothers are noticeably nervous the first time they encounter him. As Octagon says, Appoplexians are meaner and stupider than they are. Their concern quickly proves justified, as Rath pummels them and anyone trying to help them, culminating in the Vreedles being thrown out into the vacuum of space at the end of it all.
• Immune to Bullets: Neither bullets nor lasers can hurt him.
• Jack of All Stats: He isn't the physically strongest alien (Four Arms, Humungousaur, or Way Big outperform him), he isn't the most agile alien (Crashhopper, Jetray, Spidermonkey, Stinkfly and XLR8 are more nimble), and he isn't the most skilled martial artist (that would be Kickin Hawk). But he performs well in all physical areas, which makes him one of Ben's most useful aliens for hand-to-hand combat.
• Jerk with a Heart of Gold: Despite his claims to the contrary, he warms up to the puffball he was escorting, reacting violently when it was eaten.
• Large Ham: It wouldn't be Rath without him shouting "LET ME TELL YOU SOMETHING..." and charging ahead with dramatic wrestling moods.
• Lightning Bruiser: He's extremely strong, can survive dropping from thousands of feet in the air, and isn't affected by lasers at the slightest (there are burn marks around him). The only things that prevent him from mauling everyone in sight are his limited intelligence and Hair-Trigger Temper.
• Leeroy Jenkins: Is always itching for a fight and will charge head-first into danger.
• Literal Ass-Kicking: One of his signature moves is called "Sirius Butt-Kicking," which is Exactly What It Says on the Tin.
• Mad Libs Catchphrase: "Lemme tell ya somethin', (full name here)..." Word of God states that, in his ultimate form, Rath's catchphrase becomes: "Lemme tell ya FIVE things, (full name here)..." invoked
• Masked Luchador: In "Secret of Dos Santos", Skurd fixes the Omnitrix error that made Rath naked, giving him a green luchador outfit and making him speak in Spanish.
• Meaningful Name: (W)Rath, the "Appoplexian". Doesn't get much more obvious than that.
• Mega Neko: He looks like a big anthro tiger.
• Metaphorgotten: Most of Rath's Pre-Asskicking One-Liner speeches tend to be utterly nonsensical for the most part, something that other characters are more than happy to lampshade.
  • In "The Con of Rath"
    Rath: A man's food is his castle!
    Ocatagon: I believe what you done there is mixin’ what you might call metaphors.
  • And in "Above and Beyond"
    Rath: You want a piece of Rath? You got a piece! But you just bit off an eye bigger than your stomach can chew!
    Manny: That made no sense.
    Rath: (Beat) I KNOW!
• Naked People Are Funny: Omniverse reveals that Appoplexians have a sense of shame, and typically wear clothes. Rath doesn't. According to Word of God, Rath is naked because of a horrible error on the part of the Omnitrix. invoked
• The Nicknamer: Calls Vulkanus "Baby Man", and Seven-Seven "Karate Man".
• Nigh-Invulnerable: Getting hit with a laser doesn't phase him, nor does dropping out of the sky and causing a giant crater of him knock him out.
• Ninja Pirate Zombie Robot: An alien who looks like a tiger and fights and acts like a wrestler. That sums him up.
• No Indoor Voice: This is pretty much his standard way to talk. He only lowered his voice once in the whole franchise.
• One-Winged Angel: In "Malgax Attacks", Albedo uses his Ultimatrix to go Ultimate Rath.◊
• Panthera Awesome: Doesn't get more awesome than a muscular, bipedal tiger with Wolverine Claws and the same strength, endurance and agility you'd expect of one.
• Papa Wolf: After warming up to the Tiffin. To the point that he'd knit a sweater out of an alien's organs if it declared war.
• Pass the Popcorn: Discussed by Kevin and Gwen; they both admit that Rath is the only alien that makes them want to sit down with some popcorn and enjoy the show.
• Shout-Out: Personality-wise, he's a tiger version of wrestlers like Hulk Hogan and Randy Savage. His appearance such as his claws and animalistic nature make him a Wolverine Wannabe, with Ultimate Rath blending it with Kraven the Hunter.
• Stellar Theme Naming: His wrestling moves are based on stars, such as Polaris Pile-Driver. It is lampshaded when it comes to "Sirius Butt-Kicking!"
  Manny: So, is that "Sirius" like the star, or "serious" like important?
  Rath: Like the star!
• Stupid Good: Ben's intelligence decreases dramatically in favor of heightening his aggression, though he remains a heroic figure. Most of the time it's played for laughs anyways, with a notable example being when Rath screams at gravity and the Impact Silhouette he leaves in the ground in "Prisoner 775 is Missing", instead of trying to focus on the bigger picture of what's going on.
• Spikes of Villainy: Ultimate Rath is used by Albedo and is covered in claws and spines.
• Super-Strength: He can throw a tank.
• Success Through Insanity: There's no denying that Rath is utterly nuts, but the fact that he tends to back up his inane Badass Boasts with some legitimate fighting prowess and Large Ham dialogue makes it all the more worth it. Even Gwen and Kevin admit that they like to sit back and watch what happens whenever Ben turns into Rath.
• Third-Person Person: Outside of his catchphrase, Rath almost always refers to himself in the third person.
• Tsundere: A parodied modern Harsh one; he has a soft spot for his friends, but usually blows them off with a "Whatever!"
  Rath: Let me tell you something, alien partner that I never wanted in the first place, but am begrudgingly starting to like, IN SPITE OF MYSELF!
• Unstoppable Rage: He more-or-less exists in this state at all times. Ben usually selects him for opponents that he has no desire to hold back on.
• Weaksauce Weakness: "Gone Fishing" reveals that Rath, being a cat-like alien, is terrified of water. Ironic, considering that tigers have no issue with swimming to pursue their prey.
• When All You Have Is a Hammer…: Kevin notes that all of Rath's species believes that anything can be solvable by hitting it. According to Rath, this is incorrect — "Sometimes you just need to hit things a lot."
• Wolverine Claws: Except he only has one on each hand. In the middle of them. Ultimate Rath has an extra claw on each hand, making him closer to the Trope Namer.
• Wolverine Wannabe: Rath is from a tiger-like alien species of a Blood Knight Proud Warrior Race called Appoplexians, who possesses Wolverine Claws, are aggressive, and love trash talking. His design is even reminiscent to his first costume◊.
• Wrestler in All of Us: Piledrivers and Armbars galore. "Secret of Dos Santos" takes this to its logical conclusion and turns him into a luchador.

Spidermonkey

Spidermonkey/Ultimate Spidermonkey (AF-08, UA-01, RE-173-176)

^{Click here to see Ultimate Spidermonkey}

^{Click here to see Ultimate Spidermonkey as used by Albedo in Omniverse}

Voiced by Dee Bradley Baker, Paul Eiding (Albedo as Ultimate Spidermonkey, Omniverse)

Spidermonkey was sampled from an Arachnichimp, a species of sentient monkey-like aliens with arachnoid features from Arachscimia. Arachscimia is a jungle-like planet with incredibly tall trees and large, dangerous predators on the ground. As a result, Arachnichimps have to live in the trees in elevated houses to survive.

Ben 23's version is named Mr. Monkey.

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• Acrofatic: Ultimate Spidermonkey is remarkably faster and more agile than his massive size would suggest.
• All Webbed Up/Projectile Webbing: He shoots sticky webbing from his tail to trap enemies, blind them, or swing across long distances.
• Breath Weapon: His Ultimate form shoots webbing from his mouth.
• Building Swing: He can travel via web-slinging in the same vein as Spider-Man.
• Early Installment Character-Design Difference: Inverted with Ultimate Spidermonkey. In Ultimate Alien, Ultimate Spidermonkey separates the "spider" and "monkey" elements, being a relatively normal gorilla with two extra eyes and two massive forearms and tiny legs, held up by four spider legs coming out of its back. Omniverse goes the opposite direction and essentially makes a gorilla version of a normal Arachnichimp, as Ultimate Spidermonkey is now a six-armed gorilla using its arms to hold itself up with a full eight eyes and two side-mandibles on its head.
• Evolution Power-Up: Though he gains a massive boost in strength, Ultimate Spidermonkey's powers are dependent on which version is in question due to the huge change made to his four extra limbs. In Ultimate Alien, he gains four giant spider legs that he can use similarly to Doctor Octopus's arms, either to increase his mobility or be used as sharp weapons. In Omniverse, his extra legs become extra arms which add to his strength and dexterity. In both versions, his spinner moves from his tail to his mouth when undergoing evolution.
• Fragile Speedster: As nimble as he is, he's not one who can easily bounce back from damage.
• Lightning Bruiser: Ultimate Spidermonkey is as nimble as regular Spidermonkey, but with enough strength to rival Four Arms.
• Multi-Armed and Dangerous: Spidermonkey has four arms, and has an exceptional mix of strength, speed, and agility. In Omniverse, Ultimate Spidermonkey has six arms and is even stronger.
• Projectile Webbing: He can shoot his webs out of the tip of his tail. His Ultimate Form shoots it out of his mouth instead.
• Spider-Man Send-Up: He has virtually all the same powers as Spidey (minus Spider-Sense) and becomes noticeably sillier and more jokey in this form. Ultimate Spidermonkey and his Spider Limbs (at least in Ultimate Alien) is a shout-out to Spider-Man's Arch-Enemy, Doctor Octopus.
• Spider Limbs: Ultimate Spidermonkey trades the additional arms for four spider-like legs. In Omniverse, the spider legs are replaced with gorilla arms.
• Super-Strength: He's much stronger than his size would suggest, able to pick up a street light and send Ultimate Kevin flying across the block with it. Ultimate Spidermonkey is even stronger, enough to match Four Arms and briefly trade blows with Ultimate Aggregor.
• Super-Toughness: Ultimate Spidermonkey is shown to be able to survive a close-range nuclear explosion.
• Wall Crawl: Unsurprisingly, he can stick to walls, much like a real spider and the webhead he's based on.

Swampfire

Swampfire/Ultimate Swampfire (AF-01, AF-46)

^{Click here to see Ultimate Swampfire}

Voiced by Dee Bradley Baker (Alien Force, Ultimate Alien, Omniverse proper), David Kaye (Omniverse 2 video game)

Swampfire was sampled from a Methanosian from planet Methanos. Methanos is a swampy planet, bathed in stinky methane that would be toxic to humans. Its inhabitants, the Methanosians, originally were carnivorous plants that over time evolved into humanoid herbivores. They possess the ability to generate methanes and use it to produce fire.

Ben 23's version is named Mr. Mucky.

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• Art Evolution: In his first appearance in Omniverse, he was almost unchanged from his Alien Force/Ultimate Alien design. In "Charmed, I'm Sure", he was redesigned to look more "fiery".
• Combo Platter Powers / Composite Character: Combines the powers of Wildvine and Heatblast into a single form.
• Cute Little Fangs: Though only visible when up-close. They're most notable at the start of "Prisoner 775".
• A Day in the Limelight: After being Demoted to Extra in Omniverse, the episode "Charmed, I'm Sure" centers around Swampfire's blossoming puberty. He's the only alien Ben turns into for the entire episode as he transitions into a more powerful form.
• Demoted to Extra: In the first few seasons of Omniverse, Swampfire was mostly limited to a few non-speaking cameos despite being one of Ben's most prominent aliens in Alien Force and Ultimate Alien. Subverted in the episode "Charmed, I'm Sure," where he plays an important role for the whole episode.
• Disney Death: Both were briefly lost in the battle against Eon, who turned them to dust, but were "revived" by Ben 10,000 at the end.
• Elemental Powers: Both Chlorokinesis and Pyrokinesis, though the latter is limited to expelling it from his palms.
• Evolution Power-Up: Ultimate Swampfire has one of the most drastic appearance changes out of every Ultimate form. His vines change into wood and his flowers turn into some volatile blue goo sacs, which extends to his seed bombs. Whatever blue goo courses through him also amplify his flame-shooting hand vents, giving his flames the appearance of lasers. Strangely enough, despite being made of wood, Ultimate Swampfire's wooden body parts are still conductive.
• Green Thumb: In addition to being himself a plant, he can generate a gas that allows him to control plants. If there are no plants in the area, he can also spawn seeds that produce incredibly fast-growing plants.
• Good Thing You Can Heal: Regular Swampfire tends to frequently get torn compared to other aliens, only to regenerate in the process to give opponents a new one.
• Healing Factor: He can grow back limbs, his head, even his entire body when he's been cut to pieces. Ultimate Swampfire trades this for enhanced durability. Though Matt Wayne believes Ultimate Swampfire should still be able to regenerate, as it's a trait that natural selection would favor. invoked
• Hunk: Post-puberty, he gains a Lantern Jaw of Justice and looks more like a superhero. And yes, he's hot!
• Iron Butt Monkey: Very frequently gets shredded, mutilated, or even blown up to pieces compared to other aliens.
• Kamehame Hadoken: Ultimate Swampfire can shoot a large blast of blue flames from his palms.
• Knockout Gas: He can release this from his palms.
• Lantern Jaw of Justice: After he blooms, his chin is much more pronounced, giving him a more traditional superhero-esque look.
• Lightning Bruiser: He is physically strong enough to defeat an armored alien in one punch, yet is as fast and agile as a human being.
• Mid-Season Upgrade: In "Charmed I'm Sure", Swampfire goes through puberty and evolves into a new, more powerful form. His ability to control plants and summon vines now function at will (before he had to spray a plant with gas to control it, and his vines only sprouted up wherever he tossed his seeds) and the vines he can summon are absolutely massive.
• Mythology Gag: His adult form is based on unused concept art.
• Plant Aliens: If you hadn't noticed by now, Swampfire is a humanoid plant.
• Playing with Fire: He can shoot fire and throw fireballs from his hands.
• Puberty Superpower: Around the age of 16, Methanosians go through puberty and mature into a new, more powerful form. Similarly to Big Chill's pregnancy, this had an effect on Ben's human form, causing him to break out with acne.
• Super-Strength: Not the strongest alien in Ben's arsenal, but he still has enough physical strength to knock down armored knights, not to mention causing a DNAlien weather tower to crumble down.
• Suspiciously Similar Substitute: To Heatblast as Ben's fire alien in Alien Force and Ultimate Alien before the alien form returns and they both get used. He also takes the place of Wildvine as the plant-based alien, with young Ben even calling him a "copy of Wildvine" upon seeing him.
• Swamp Monster: Swampfire seems to invoke this. He is a Plant Person with his body composed of vegetation and has Green Thumb powers. His species is stated to have evolved from carnivorous plants.
• Vine Tentacles: After his puberty, he can grow vine whips from his hands that have burning tips.
• When Trees Attack: Ultimate Swampfire resemble a tree.