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[[folder:A-C]]
* AlternativeCharacterInterpretation:
** Some fans assume that Ben's return to immaturity might be caused by him accentuating his JerkassFacade as a way to prevent himself from getting too serious and as such prevent him from going KnightTemplar like he almost did at the end of ''Ultimate Alien''.
** Due to Dimension 23 Tetrax being introduced [[KickTheDog doing actual rampages in a human city]], a lot of fans assume [[spoiler: he is still evil, or at least less moral than his mainstream counterpart, and [[PsychoForHire just happened to have been hired by Azmuth at this point]]. This theory is further supported by the fact mainstream Azmuth has been shown hiring villains before (he did recruit Sunder in ''Ultimate Alien'' to get the Unitrix back). Also lending credence to this theory is that [[BountyHunter Sevenseven]] is also on 23!Azmuth's payroll, and does similar actions.]]
** [[spoiler:Has Phil's mind been completely consumed by his Terroranchula mind, or was he just EvilAllAlong? The episode presents it as the former, but then Phil reappears as a member of the Rooters who has apparently been with them for some time now, which presents a good case for the latter.]]
* AngstWhatAngst: [[spoiler: For someone who just watched the entire universe get destroyed right in front of him, Ben seems unusually cheerful. Granted, he was able to sorta bring everyone back via Alien X, but still he should have SOME KIND OF GRIEVING!]] Head on over to FridgeHorror to see what the end of the episode might entail and you'll understand what I mean.
** He also expresses little more than mild surprise when learning [[spoiler:Eon is an alternate universe version of him]], and doesn't seem at all concerned that [[spoiler:he might become a FallenHero in one of the future timelines]].
* AntiClimaxBoss:
** Dr Psychobos. The series builds him up as an EvilCounterpart to Azmuth and hinted he was more powerful than he appeared by having him easily subduing both his associates at one point. Moreover, he was one of the few villains to actually escape a confrontation with Ben while getting what he wants. Yet, he is easily outsmarted by Azmuth in "Showdown Part 1". Granted, he ''is'' a NonActionBigBad, but you'd have expected him to be a bigger challenge for Azmuth as a mastermind.
** For the matter, Khyber and his pet aren't exactly impressive either in the same fight: the struggle between Ben and his pet essentially sums up to Ben being either overpowered or incapacited by the Nemetrix predators, until Azmuth figures out how to take control of the pet. Especially irritating when Ben [[AesopAmnesia gets easily incapacitated twice by Hypnotik's abilities, even though]] ''[[AesopAmnesia Malefactor]]'' [[AesopAmnesia had him figure out how to resist this specific predator's ability]].
** Sixsix, Sevenseven and Eighteight in "Vilgax Must Croak". For the whole episode, they pursue the Plumbers inside Incarceon and almost eliminate them, with a single one of them sending them running. When the Plumbers come back and confront them again... they immediatly surrender, despite being clearly stronger than them.
** [[spoiler:Khyber's new pet's [[SuperMode Ultimate Form]] is defeated ridiculously easily by Water Hazard before it could get to do anything impressive.]]
** [[spoiler:Zs'Skayr and Lord Transyl. Thanks to Viktor betraying Zs'Skayr, Ben is able to turn into Atomix and create a ball of light that kills Zs'Skayr and weakens Transyl enough for Viktor to capture him, put him in a coffin, and push the coffin towards the sun.]] The fun thing is how the victory music starts playing as soon as [[spoiler:Ben turns into Atomix,]] before he even does anything. It's like a musical LampshadeHanging.
** [[spoiler:Charmcaster in "Third Time's a Charm". She transforms into a dragon, and Ben defeats her by faking a magic trick, and tricking her into to reaching into her own bag, activating a trap that Gwen set, trapping Charmcaster in there.]]
* AssPull:
** While the climax of "Showdown, Part 2" is awesome, no clear explanation is given about how [[spoiler:Ben got Feedback back during his fight with Malware; he gets eaten by Malware, has a vision of his past self with which to reconcile his issues about losing Feedback, and then suddenly regains said form even though it was made perfectly clear that the Omnitrix could ''never'' get it back]]. The scene is frankly a huge DeusExMachina. Amusingly enough, [[WordOfGod Matt Wayne himself]] admitted he had no idea what happened during this scene when asked about it.
** [[InsignificantLittleBluePlanet Earth]] suddenly being a major strategic point to start an invasion of the Galaxy at the beginning of "Frogs of War", even though all three previous series established it as a backwater planet.
** Gwen not liking Lucy to the point of suspecting her of being a traitor in "Mud is Thicker Than Water." In the one Original Series episode where Lucy appeared, there was next to no interaction between the two, but they didn't appear to dislike each other at all, and even in the flashback to their child selves ''in the very episode'' Gwen was only mildly irritated with her (far from actual dislike) and got over it quickly since she had Ben to be angry with. Plus, the issue is solved by the end of the episode, most likely to not be mentioned again ever, so what was the point of this all of a sudden?
** [[spoiler:Gorvan being the real spy at the end of ''Mud Thicker Than Water'']]. There was no foreshadowing, we didn't even ''know'' [[spoiler:he was part of the Plumbers]] until TheReveal (a fact already hard to explain by itself; see WhatAnIdiot below) and this basically comes out of nowhere just to confirm once and for all that [[spoiler:Lucy was a RedHerring]].
** [[spoiler:Blucick and Driba ''repairing'' the Annihilarg. They might be GeniusDitz, but it's really hard to swallow that they were smart enough to fix a crushed device from an ancient extinct species (plus, who would have been stupid enough to let them touch the remains to begin with?).]]
** [[spoiler:Gwen and Kevin [[ContrivedCoincidence being up in Earth orbit for a college astronomy project]] at the beginning of ''For A Few Brains More'' to save Max, Rook, Ben and Azmuth.]]
** 12-year-old Kevin's appearance in ''From Hedorium to Eternity''.
** Azmuth's [[spoiler:Omnitrix disabling remote]] in ''Malgax Attack''. This one especially is blatant, as not only does it raise the question of why he [[spoiler:never tried using it before, especially when Albedo kidnapped him in the Duel of the Duplicate arc]], but it also contradicts a large majority of the conflicts in the show, considering how many antagonists were motivated by [[spoiler:their desire to get the Omnitrix for their own selfish goal]]. In fact, [[spoiler:this was the ''very reason'' Azmuth sent the Omnitrix on Earth in the first place]].
* AuthorsSavingThrow:
** This series has been said to attempt to reconcile the conflicting styles of the first ''Ben 10'' series by Man of Action and the two sequels by Glen Murakami and Dwayne [=McDuffie=]. So far, [[BrokenBase fans are really disagreeing about whether they succeeded or not]].
** A question a few fans nagged about was why the Plumbers were working again in the sequels when they were retired in the first series, plus all of the alien members despite being an Earth force. "Malefactor" explained that after the first series, they decided to reinstate the Plumbers.
** One was apparently attempted at the end of ''For a Few Brains More''; after many fans complaining that the so-called "perfect" Omnitrix actually worked worse than the original one or the Ultimatrix, Ben actually asks the same question to Azmuth, only for him to answer that Ben is pushing too hard, resulting in the Omnitrix randomizing its time limit. Wether this explanation works or not is, like many other things, [[BrokenBase subject to debate amongst fans]].
** The three [[AbortedArc Aborted Arcs]] from ''Ultimate Alien'' have been salvaged as much as possible:
*** Zs'Skayr goes into Dr. Viktor's body and consumes King Xarion's soul, freeing Dr. Viktor's mind.
*** A [[http://ecx.images-amazon.com/images/I/51TikJCx20L._SL500_AA300_.jpg graphic novel]] will show what happened to Elena Validus and the Hive nanochips.
*** Charmcaster's new ''Omniverse'' arc still follows up from her aborted ''Ultimate Alien'' one rather than it just being ignored entirely.
** AlienForce got some flak for allowing Vulkanus to purchase and attempt to terraform the Earth (which would kill everything on it), with the indication that his actions were entirely within galactic law. In "Collect This", when Collectimus buys Earth from Simian, Rook explains that no, this is not legal.
*** ''Rooters of All Evil'' was attempted to be one: ''Alien Force'' also received criticism for making everything be about aliens, turning Ben, Kevin, and Gwen, all into HalfHumanHybrids and then introducing the Plumber's Kids, which seemed to imply Plumbers went around making and abandoning children. "Rooters Of All Evil" retcons most of this; [[spoiler: Kevin is in fact fully human, Osmosian is turned into a term for what is basically [[Comicbook/XMen mutants]] and the Plumbers kids are genetic experiments that Max was mind controlled into caring for.]] The reactions of the fans, however, [[BrokenBase were not all positive]].
* BadassDecay:
** While he has his LetsGetDangerous moments, Ben is still portrayed as much more bumbling and less competent in this show than he was in the two previous sequels, and has a bad tendency to be turned into a ButtMonkey. Partially justified in earlier episodes due to his lack of familiarity with the new Omnitrix, but still extremely irritating, and as the series progresses it becomes less and less credible.
** Rath was portrayed in ''Alien Force'' and ''Ultimate Alien'' as a CrazyAwesome ImplacableMan whose sole weaknesses were his HairTriggerTemper and limited intelligence. ''Omniverse'' flanderizes his cat-like aspects, making him [[WeaksauceWeakness afraid of water]] ([[CriticalResearchFailure Despite tigers not having problems with water like cats do in real life]]), [[WeaksauceWeakness distracted by string-like objects and laser pointers ]] and vulnerable to [[HarmlessVillain Nyancy-Chan]]'s MindControl power (even though it didn't work on Rook, who also is a cat-like alien). He also tends to suffer TheWorfEffect a lot, one of the most humiliating cases being when he got defeated by the Circus Freak Trio, who were Ben's personal ButtMonkey in the Original Show. Essentially, they're flanderizing his comedic aspects at the expense of his badass ones.
* BaseBreaker:
** Bloxx. Some fans think he is an original, delightfully weird alien and raise him to EnsembleDarkhorse level. Other think the idea of a Franchise/{{LEGO}}-based alien life form seems silly and doesn't make any sense, even in the ''Ben 10'' universe.
** For similar reason, Liam and his Omnitrix counterpart Kickin Hawks are either considered hilarious or completely stupid.
** While Rook has indisputably become an EnsembleDarkhorse, there are some fans who still feel like he is a CanonSue SpotlightStealingSquad who make Ben's incompetence painfully obvious. Not helped by the fact the series itself points out how Rook has been saving his butt quite often. He gets gradually better as the story goes on, though.
** Khyber is either a CreepyAwesome EgomaniacHunter, or a generic villain who relies on his dog to fight his foes. This division of opinion seems to have subsided by "Of Predators and Prey", where it's revealed that [[spoiler:he was hired by Malware and he is ''not'' the BigBad as thought]].
** Blucik and Driba are, depending which part of the fandom you ask, hilarious PluckyComicRelief or incredibly annoying {{Creators Pet}}s who cause more problems than they solve.
** Argit: an annoying CreatorsPet who appears too often or the best damn character in the show.
** Esther: a good character and love interest or a complete Relationship Sue.
** Ben himself, some frustrated at what they feel is serious character degradation and his lack of maturity, others are either okay or just don't care about it.
** Atomix is either loved for his hammyness, badassery and being a ContinuityNod to the Original Series' episode ''Ken 10'', or hated for having a ugly, robotic-like, toyetic design and being a GodModeSue.
** Albedo manages to be a Base Breaker amongst Alien Force fans: some are happy he is turned into a genuinely effective villain again, others are mad he had to devolve from a sympathetic AntiVillain to a CardCarryingVillain for this.
** Kai Green; Some fans [[RescuedFromTheScrappyHeap find her more likable than she was in her first appearance]] and appreciate that her being Ben's confirmed future wife makes the Ben 10,000 future canon again; other feels her relationship with Ben was [[StrangledByTheRedString forced]] and she gets too much CharacterShilling (she is hinted to be worthy of [[spoiler:''pulling Excalibur out of its stone'']], even though none of what she ever did before suggested she was noble enough for this), not to mention the fact her being confirmed as Ben's future wife makes every single other LoveInterest introduced in this series ([[RomanticFalseLead Esther]] especially) entirely pointless.
** The Rooters, due to being the source of a controversial CerebusRetcon involving Kevin and the Plumbers' Kids. Although they have managed to obtain some popularity due to being the first major villains since Malware to shift the tone into a more serious one.
** Skurd. Either an awesome character with awesome battle capabilities, or yet another [[TheScrappy Scrappy]] CreatorsPet.
* BrokenBase: At this point the base has been broken down into a coarse powder.
** A common division: Original ''Ben 10'' and/or Derrick Wyatt's fans who are glad to see the show going back to its original roots and become "fun" again, and ''Alien Force''[=/=]''Ultimate Alien'' fans who are afraid Wyatt might be removing everything brought by the sequels (including the good parts) for the sake of going back to the original show. The fact he confirmed that several sequel episodes would be CanonDiscontinuity, that arcs started in the previous series have [[AbortedArc been aborted]], and hinted several times he wasn't really a fan of the sequels ''doesn't'' help. And then there are those who [[FirstInstallmentWins still believe in the original series only]] and see both ''Alien Force'', ''Ultimate Alien'' '''and''' ''Omniverse'' as crappy, in fact resenting ''Omniverse's'' attempts at throwbacks to the original.
** While many aliens' designs ''had'' been criticized in the ''AF/UA'' era, especially later ones like Eatle, Jury Rigg, and Fasttrack, many others were already good to begin with, raising some controversy about the point of redesigning them as well (especially the original series aliens, whose designs were critically acclaimed for most anyway). Most notable examples of those unnecessary redesigns include Fourarms now having a mustache and Big Chill being now a bulky bug instead of a skeleton-like skinny creature.
** The theme song; some are glad the show gets an actual song with lyrics instead of an instrumental piece again, others feel it's overly childish, even compared to the original show's one;
** The ContinuityPorn, particularly the flashback around 10 years old Ben; a lot of fans are glad about it, since it brings back an original series feeling; others feel that it's a bit forced and unnecessary (what's the point of trying to make 15 years old characters more like their original selves if their original selves will show up in flashback episodes on regular basis anyway?) and will only end up wasting episode that could have been focusing on the plot.
** [[OmniscientDatabase Primus and the Codon Stream]] being RetGone; while many fans who disliked the concept are glad it's gone, others are mad it was just classified CanonDiscontinuity and point out this creates only more plotholes.
** The fact the show is privileging a DenserAndWackier approach and RuleOfFunny over a good plot also is starting to bother a lot of fans, especially the return of Ben's ButtMonkey status and the degradation of many villains, even ones that start off threatening in ''this'' series, to jokes.
** Then there's the animation style in general, from realistic to "cartoony." Basically, see ''TransformersAnimated.'' Part of Wyatt's SignatureStyle is a design scheme that people in the biz call "stylized" and people not in the biz call "Ow, my eyes!" (Or, "Well, it fits this lighter series." That's why it's a base-breaker.)
** [[ArchEnemy Vilgax]] being so far DemotedToExtra; fans who thought he was overused in previous series are glad he finally makes way for other villains, while others complain about him missing despite his importance in Ben's rogues gallery. Similarly, there are quarrels about weither his absence will allow to prepare his return as a proper threat or if it just ends up pushing him further in VillainDecay by making him the butt of jokes whenever he gets a mention.
** The less said about what fans think of [[CosmicRetcon Ben rebuilding the Universe as Alien X]], the better.
** The retcons in "The Rooters of all Evil": [[spoiler: Kevin isn't part alien; Osmosians are just humans with a genetic component that gives them powers, and Kevin's is energy/matter absorption. The Plumber's Kids aren't hybrids; they're humans infused with alien DNA. Max never had a partner named Devin Levin; he never existed, and their partnership was a false memory implanted by Proctor Servantis so that he'd look after Kevin and the Plumber's Helpers. On one hand, this brings things closer to the original series; on the other hand, it basically nullifies much of ''Alien Force'' and ''Ultimate Alien'' and tries to fix already confusing retcons by making even ''more'' retcons, messing up the continuity further.]]
** The ending of ''Third Time's a Charm'', [[spoiler: On one side there are those who like it because while trapped in her own bag, Charmcaster is now under the care of two people (Hex and Gwen) who care about her and is no longer being influenced by the likes of Adwatia and Darkstar, and they feel this is a nice compromise between doing a HeelFaceTurn and not doing one. On the other side, others just wanted a full-on HeelFaceTurn rather than more setup for one, found Charmcaster's defeat to rely on a very old clich, and hated that while Darkstar was arrested, Adwatia, easily the more evil of the two, teleported away and will likely stay a KarmaHoudini due to the series ending soon afterward.]]
** "Most Dangerous Game Show" may just be the most divisive episode in the history of the franchise.
* CharacterRerailment:
** Zombozo had inexplicably lost his supernatural abilities in ''Ultimate Alien'', and went from a NightmareFuel-inspiring MonsterClown to a DenserAndWackier HarmlessVillain at the beginning of ''Omniverse''. ''Something Zombozo This Way Comes'' restores him to his supernatural HumanoidAbomination status from the Original Series, and provides an actual explanation for the loss of his powers in the previous series.
** Zigzagged with Ben. His personality owes to the exaggerated [[TookALevelInDumbass moron]] from Season 3 of ''Alien Force'', much to the irritation of the fans who liked him as a more competent and heroic character, but some episodes like "Malefactor" or "Max's Monster" do showcase him as smarter and more competent. Unfortunately, by the next episode he usually tends to [[AesopAmnesia get back to be a moron]], and the writers have so far yet to settle on either portrayal.
** Kevin's redesign and [[TookALevelInJerkass more borderline sociopathic attitude]] is seen by some as an obvious attempt at this, much to the chagrin of fans who preferred how Kevin was before.
** Eon's design is portrayed as closer to his movie self. Considering many thought the ''Ultimate Alien'' version actually was cooler than his movie self, whether it's a good thing or not is up to debate. With that being said, he's much more like a [[CompositeCharacter mixture]] of the various versions, taking the basic backstory of the ''Ultimate Alien'' incarnation ([[spoiler:[[FallenHero he's Ben]] according to WordOfGod, as already hinted by him and Ben 10,000 sharing [[TheOtherDarrin their latest VA]]]]) as well as threat level, and the movie incarnation's appearance. Interestingly, there are also aspects of his movie self that were present in UA but left out here, most notably his ''entire head.'' It's like UA used half of Movie Eon's design, and Omniverse uses the half that UA ''didn't.''
** Albedo seems to be on his way to going back to being a fairly competent EvilCounterpart to Ben as opposed to the ButtMonkey (when this show itself has exaggerated Ben's ButtMonkey traits, ironically) he eventually became in ''Ultimate Alien''. Sadly, the same cannot be said for his motivations. See MotiveDecay.
** Charmcaster's design, personality, and voice (though it has always been done by KariWahlgren) much more closely resembles her original ones than the ones from ''Alien Force'' / ''Ultimate Alien''...except [[DenserAndWackier zanier.]]
** Some real effort to undoing villains' BadassDecay seems to be ongoing, with various level of success. Vilgax is given a TheBadGuyWins moment, but also has much less appearances and is treated more like a joke by the other characters than before. Albedo is promoted to BigBad rank and made a darker, more threatening villain again after having been downgraded to ButtMonkey after his first couple of appearances in AF/UA (though [[spoiler:Azmuth�s treatment of him at the end]] nullifies this effort a bit); Darkstar was back to his old badassitude level after having fallen even farther than Albedo had (though he slips once he gets his Mike Morningstar looks back.) It's a shame Psyphon is ''more'' of a ButtMonkey every episode when he was so cool that first time he operated solo, but then, I guess ''someone's'' got to be the HarmlessVillain and [[HumanoidAbomination it sure ain't Zombozo]].
** Vilgax ''finally'' goes back to being portrayed as a fully serious and competent villain in "And Then There Were None" by [[spoiler:basically destroying all of creation except the one timeline he was in.]] A shame it only lasts an episode before he receives a humiliating beat-down, not to mention he is turned back into a joke by ''Vreedlemania''.
*** Things improve for him again with "Malgax Attacks", however. Vilgax is portrayed as TheHeavy. While its Albedo's plan to attack Galvan, Vilgax, [[FusionDance now wearing armor made of Malware's remains]], spends the entire episode [[CurbStompBattle tossing Ben around like a ragdoll]], even beating Atomix, who is infamous for being a walking DeusExMachina. His loss is also dignified: aside from a slapstick moment of Skurd saving Ben by sticking to Vilgax's head, he's defeated in a fair fight that ends with him HoistByHisOwnPetard.
* CompleteMonster: The ArcVillain of the 8th season, Maltruant, is a rogue [[TimeMaster Chronosapien]] bent on ruling all of time and existence. He masterminded the original Time War in his first bid for universal control, but was defeated and his body separated across time by Professor Paradox. Seeking to restart the Time War and win, He hired Dr. Psychobos to help repair himself. After his CoDragons Subdora and Exo-Skull complete repairing his body, Maltruant turned on Dr. Psychobos, easily defeated Ben Prime and Ben 23, and left both for dead in Mad Ben's dimension with his minions to restart the Time War. Once he travels to the time period of Ben 10,000 to steal the [[DoomsdayDevice Anihilaarg]] and the [[AmplifierArtifact Dwarf Star]] so he can create a more deadly weapon, Maltruant traveled back to the very beginning of the universe and snuck aboard the [[{{Precursors}} Contemelia's]] ship, where he switched their Anihilaarg with his own in order to recreate the universe in his image. Extremely power hungry and so egomanical that when he met the Contemelia (who always appear in the form of who or what one holds dearest in their hearts) [[{{Narcissist}} he saw three alternate versions of himself]], Maltruant cements himself as one of Ben's most monstrous enemies.
* ContestedSequel: Let's face it; with the already BrokenBase caused by the two previous sequels, this show was dead on arrival.
* ContinuityLockout: Perhaps inevitable, considering the fact that the show references elements and brings back threats that haven't been seen in a long while (Megawhatts, a ''one-off'' threat from the first series), as well as coming right after two of the most arc-oriented entries in the franchise. Taken to ridiculous extremes when they use Gorvan, a character who ''only appeared in the first Alien Force video game''. Anyone who has never played the game can't possibly know who he is, yet he is treated like he has always been a recurring villain.
* CreatorsPet:
** Feedback in the eyes of some fans; he is introduced as being Ben's favorite alien when he was 11, despite the original show clearly establishing Fourarms as Ben's favorite in the original series era. Few reasons about why Ben likes him so much are given, with him simply saying he is "[[CharacterShilling cool and awesome]]" or mentioning "he felt like he was a part of me" (It was hinted in ''Showdown Part 2'' that [[spoiler:the form had an addictive effect on him]], but [[TheyWastedAPerfectlyGoodPlot this was never explored further]]). He also tends to be conveniently [[ManOfKryptonite remarkably effective to defeat a lot of specific powerful opponent]], to the point of almost becoming a DeusExMachina (such as when he turns out to be the ideal alien to defeat [[spoiler:Argost]], or when he manages to defeat Ultimate Humongousaur easily, [[FridgeLogic even though Ultimate Humongousaur's abilities aren't energy-related]]). One of the most infamous examples is the series' finale, where [[spoiler:he somehow proves a more effective form to contain Maltruant's DoomsdayDevice than ''[[CrystalDragonJesus Chromastone]]''.]]
** Blucik and Driba are adored by the writing staff; they got two episodes entirely dedicated to them (and the first one, ''Blucik and Driba go to Mr Smoothies'', is one of the writers' favourite episode), a lot of screentime (including in several season finales) and Derrick Wyatt stated he wouldn't mind them having their own spin-off show. Most fans rather see them as an extremely annoying and obnoxious PluckyComicRelief duo [[FantasticRacism with racist tendencies toward Cerebrocrustaceans]], prone to [[TheLoad cause troubles to everybody by their stupidity]] and irresponsability and generally the source of rather bad jokes.
* CreepyAwesome: Malware and Khyber.
* CriticalResearchFailure: The Rooters, who have been defined as a "Black Op" branch of the Plumbers, [[spoiler:are confronted at the end of their story arc by the [[BigGood Magistrata]], who has them punished for their acts and sent to the Null Void]]. In RealLife, Black Ops only answer to one person's authority (typically the president), and that person alone is supposed to answer for their actions if they do something wrong; realistically, [[spoiler:the Magistrata should have been the one to get the blame for what they did]].
** ''An American Benwolf in London'' has a weird case of this trope caused by AdaptationDisplacement: the [[Literature/TheStrangeCaseOfDrJekyllAndMrHyde formula created by Dr Jekyll]] is despicted as transforming the one who drinks it into an ape-like monster with superhuman strength, like Hyde usually is portrayed in media. In the novel, Hyde, while perceived by people as deformed due to being pure evil, was actually very short and not particularly monstrous or strong. This wouldn't be a problem if the series was merely doing its own version of the myth- except this formula is explicitly stated to be the same than the one described in the book at the beginning of the episode.
[[/folder]]

[[folder:D-I]]
* DesignatedHero: Some actions of the protagonists (often played for laughs) have been perceived by the fans as mean-spirited at best and downright morally questionable at worst. The most prominent examples being [[spoiler:Ben turning Harangue into an alien]] and [[spoiler:Azmuth trapping Albedo in the form of an 11-Year-Old Ben]]. While [[spoiler:[[AssholeVictim both victims clearly were meant to deserve that]]]], many felt the acts in themselves were petty, needlessly cruel and un-heroic.
** Ben especially gets those accusations: he is much more immature and egotistical than he was in previous series, much less competent, and his ChronicHeroSyndrome (which had been the ''one'' constant in all previous shows) has been considerably toned down to instead put emphasis on him wanting to have a fun (in one episode, he ends up wishing for a new Inkursean invasion ''just because he is bored''). It got so bad, some fans actually almost ''agreed'' with [[VillainHasAPoint Proctor Servantis]] when it was revealed [[spoiler:he intended to kill Ben because he thought giving so much power to an immature, irresponsible child was doomed to end badly.]]
*** A special mention for the ''Galactic Monster'' story arc, where Ben meets with Zs'Skayr right as he arrives on Anur Transyl, and [[BystanderSyndrome shows absolutely no concern with stopping him for his whole time on the planet, unless he or his allies get directly involved]]; in fact, had they not been forced to stay longer than initially intended, he would have left Anur Transyl with Zs'Skayr undefeated and still scheming.
* DesignatedVillain: Phil the former Plumber [[spoiler: not the alien monster who took over his body and mind]] was said by Ben to essentially be less redeemable than Kevin. Sure, Phil was a criminal, but he never did anything as bad as what Kevin had done in the original series. Even without the WithGreatPowerComesGreatInsanity excuse Kevin had, there wasn't anything inherently preventing Phil [[spoiler: as he was]] from turning over a new leaf. To be fair, only Ben was thinking this way, and he may have not been meant to be agreed with, and TheReveal at the climax of the episode makes it kind of a moot point anyway.
* DieForOurShip:
** Esther is either bashed by Ben X Julie / Ben X Gwen / Ben X Kevin fans, or praised by Ben X Julie bashers.
** Kai also gets hit by this from fans of those couples ''and'' fans of Ben X Esther.
* DudeNotFunny:
** The whole episode "So Long And Thanks for the Smoothies" is played for laugh, but some fans weren't really amused with what its ending implied. See the FridgeHorror section for more details.
** Not to mention Ben and Julie's breaking up ''being a gag.'' Even people [[DieForOurShip who hated the pairing]] [[BeCarefulWhatYouWishFor thought it went too far.]]
** Azmuth [[spoiler:locking Albedo in the form of a 11 years old Ben]] at the end of ''For A Few Brains More'' is played for comedy and clearly despicted as LaserGuidedKarma for [[spoiler:Albedo]], but many fans felt this was just [[DesignatedHero Azmuth needlessly being a dick to him]], especially since [[spoiler:it was Azmuth's fault if he turned out that way to begin with]]. Plus, this was perceived as a unglorified end for a character the story arc had worked so hard to rerail into a credible threat.
** Ben and Rook ''laughing'' after hearing how Billy Billion ended up trapped for all his childhood in Dimension 12. Granted, the irony ''is'' funny from the viewers' point of view, and Billy brought it on himself, but in-universe, that was still a child spending six years in an alternate dimension populated with [[KillerRobot Killer Robots]], so seeing them laught at it [[DesignatedHero kinda makes them appear as assholes]].
** A lot of fans found the gag of Ben hitting on [[AbsurdlyYouthfulMother Drew]] in ''T.G.I.S.'' more disturbing than funny.
** Charmcaster's lonely life as TheAtoner ruling Ledgerdomain [[spoiler: caused her a mental break which she's recovered from but with lingering effects making her more erratic. This is PlayedForLaughs. Granted, it's not AS bad as it could have been, since her supposed SplitPersonality is revealed to not be one at all, but the jokes at the expense of her actual personality could still be considered in poor taste by some.]]
** [[TheDreaded Vilgax]] being afraid of Ma Vreedle was probably intended to be RuleOfFunny, but for the most part it just pissed off further fans who already complained about the former's VillainDecay and convinced part of the fanbase the latter was a VillainSue.
** Ben [[spoiler:seeing the Contemelia as Mr Smoothie]]. Many feels it wasn't that funny, and just solidified Ben as a one-dimensional and shallow character.
** Most fans found the jokes about Tiffins being delicious in ''Color of a Monkey'' more disturbing than funny.
* EarWorm: A first since the original series, ''Omniverse'' has a song[[note]]a song is a musical piece that specifically has lyrics, and thus is meant to be sung[[/note]] and not an instrumental piece. And it's extremely catchy.
* EnsembleDarkhorse:
** [[HypercompetentSidekick Rook]], big time. Ironically, he was initially seen as a ReplacementScrappy for Kevin and Gwen, but as soon as trailers and later episodes revealed his status as an {{Adorkable}} BadassNormal NiceGuy, his popularity amongst fans raised considerably. By now, he is the main reason why many skeptic fans gave a chance to ''Omniverse'', and most haters consider him the best thing coming out of the show.
** Malware as well, being a major example of EvilIsCool; many fans feel his potential was underexploited in the show. And though he [[spoiler:does play a posthumous role in "Malgax Attacks" and is hinted to be still alive at the end]], now that the show is over, it kinda doesn't make a difference now.
** Gravattack, for having [[GravityMaster a power]] that is one of the most unique in the Omnitrix (one criticism of Ben having so many aliens is the lack of unique traits among them) and having a cool design and actor. It is a little disappointing that he's one of Ben's least-used aliens, though the implications of his powers [[StoryBreakerPower shows why he isn't used very often]].
** Princess Looma, the {{Yandere}} alien in love with Ben.
** Attea has become very popular, especially with the redesign.
** While the comic relief characters are hit and miss, Hobble appears to have less haters than the others, particularly since he returned in the Anur Transyl trilogy and proved to be ActuallyPrettyFunny.
** "No Watch Ben", the Omnitrix-less Ben from "And Then There Were None" and "And Then There Was Ben" seems to have drawn some liking from viewers, seeing him as less cocky and arrogant as main universe Ben and going through more CharacterDevelopment in those two episodes than main Ben has in the 50 episodes before.
** Similarly, Gwen 10 is quite well-liked due to being much nicer than her mainstream self.
* EpilepticTrees: It's popular fan theory that Ben forgot to include Primus from the Universal Rebuild in "So Long And Thanks For All The Smoothies," as DerrickJWyatt says that, pursuant to the [[ExecutiveMeddling mandate that continuity be "cleaned up,"]] whatever that means, it no longer exists. The universal rebuild has in fact been used to explain ''everything'' that is different about this series from the previous one. It helps ([[FridgeHorror or not]]) that production-wise, it is one of the earliest episodes, rather than [[OutOfOrder Episode 7]].
* EsotericHappyEnding: the Inkursian invasion StoryArc is concluded in ''Frogs of War'', where it turns out all that happened was a BatmanGambit by [[DaddysLittleVillain Princess]] [[MagnificentBitch Attea]] all along to [[TheStarscream overthrow]] her father [[TheEmperor Emperor Milleus]]. By the end of the episode, she agrees to leave Earth with the Inkursian Empire in exchange for the Plumbers keeping her daddy in custody, which is presented as an acceptable, if not entirely happy, ending. The thing is, in previous episodes, it had been clearly established that Attea was ''much'' worse than her father, being an AxeCrazy PsychoticManchild motivated by RapePillageAndBurn whereas her father was a more {{pragmatic|Villainy}} GalacticConqueror. In fact, she almost blew up Earth ForTheEvulz in her introduction episode (in contrast to her father, who only threatened to do so if she wasn't returned to him). Now, granted, she is sort of in a DatingCatwoman situation with Ben, so she will most likely avoid attacking Earth again, but that's little consolation to the rest of the galaxy.
* EvilIsCool:
** Khyber generally got good reception for this.
** Malware even more so. He rivals ''Rook'' in popularity amongst the fans.
** Psyphon was considered by many fans to have gotten cooler in this show than he was in ''Alien Force'' and ''Ultimate Alien''. Then [[TookALevelInDumbass "Bengeance is Mine" happened.]]
* EvilIsSexy: Attea; despite being from a race of frog aliens that looks rather ugly by human standards, [[CuteMonsterGirl she actually is quite attractive of her own]].
* FanficFuel: The show reveals and demonstrates the existance of various alternate timelines, each one with their own versions of Ben and the other characters. We only get to see a small number of alternate Ben and very few get actual development, so fans are free to imagine and write whatever they want about those alternate timelines.
* FashionVictimVillain:
** Dr. Animo's costume as the Ant-King. Probably intended.
** Also, Nyancy-Chan.
* FoeYay:
** Attea and Ben; it starts with him asking her (though as a joke) if she will turn into a princess if a guy kisses her; then as the show goes on, she grows more and more obsessed with fighting him personally, to the point she [[TheOnlyOneAllowedToDefeatYou forbids her forces to attack him]]. And to sell it completely, [[spoiler:she ''actually'' falls for Bullfrag, his Incursean form, to the point she offers him to come with her at the end]]. The 'kiss' on the cheek at the end, though, was with Ben ''as himself.''
** Ben and Vilgax get a little ''too'' cozy with each other in "Vilgax Must Croak". Taken UpToEleven when Vilgax does a DivingSave and ''saves Ben's life''.
-->'''Ben''': Did you just do what I think you did?
-->'''Vilgax''': I uh... I don't know what came over me...
* GodModeSue: Atomix practically is an instant win button for Ben whenever he is lucky enough to get him. Later episodes have thankfully downplayed it. "And Then There Were None" it's shown even Atomix, or at least a version merged with Alien X nicknamed "Atomic X" by Ben 10,000, [[spoiler:couldn't survive Vilgax's Chronosapien Time Bomb]]. In "Malgax Attacks" [[spoiler:Atomix loses in a fight with the Malware powered Vilgax]].
* GrowingTheBeard: "Malefactor" and afterward starts to tone down Ben's ButtMonkey tendencies and [[CharacterRerailment fix the characterization problems he's went through]], the pacing slows down, drama somewhat increased, and addressing the complaint that [[SpotlightStealingSquad Rook sometimes severely outshines Ben]] by showcasing a few episodes with Ben solo or at least with a different partner.
* HarsherInHindsight: In "Weapon XI: Part 1", some parts of the series were treated far more seriously than before.
** Ben's recreation of the universe in "So Long and Thanks for All The Smoothies" was initially treated as just as good as saving it. The only two episodes since then to directly mention it, "Collect This" and "Universe vs Tennyson", had both [[PlayedForLaughs played it for laughs]], with Collectimus complaining about LighterAndSofter as part of his role as a TakeThatAudience and with Starbeard taking Ben to court over it in a showcase of bizarre galactic bureaucracy. Proctor Servantis, however, points out with appropriate horror that ''the universe was destroyed'' and Ben was partly responsible.
** Ben's irresponsibility in general has usually been PlayedForLaughs, but Servantis argues that the extraordinary power the Omnitrix grants is not the sort of thing you want in the hands of a an immature DestructiveSavior. "Weapon XI: Part 2" ends with the conclusion that Ben, having saved the universe multiple times, was well worth the risk, but Servantis' criticisms cast Ben's less mature actions in a more critical light.
--> Servantis: That weapon on his wrist can turn him into a Tokustar. Or perhaps even a Celestialsapien. This grimy child could one day just wish everything out of existence.
* HilariousInHindsight:
** In 2010, there was a short-lived Franchise/{{LEGO}} ''Ben 10'' line based on ''[[WesternAnimation/Ben10AlienForce Alien Force]]''. Now there's Bloxx, an alien who's actually ''made'' of LEGO bricks.
** Also, when Rook can tell that Ester likes Ben, Ben doesn't believe it and responds by saying "'cuz you know everything about girls!" Turns out he does, especially when Ben realized Rook had a girlfriend.
** Eon, introduced just after the original series, was a temporal-based alien with an unexplained EvilBrit shtick, until having him face off with the also temporal-based Professor Paradox, CaptainErsatz of Series/DoctorWho, turned Eon into an {{Expy}} of the Master. Even better, the ArtShift applied to the Professor makes him resemble Creator/PeterCapaldi!
** In UltimateAlien, 16-year-old Ben countered his 10-year-old self's claim that Swampfire was "just a copy of Wildvine" by throwing seeds to spawn a mass of entangling vines, quipping "can Wildvine do ''this''?" In "Rad Monster Party", Wildvine does exactly that.
** In one of the ''Alien Force'' video games, Creator/JohnDimaggio played Vilgax, filling in for James Remar, who himself was filling in for Creator/SteveBlum. In this series, Steve Blum returns and functions as TheOtherDarrin for [[spoiler:Adwaita]], a role John Dimaggio played before.
* HolyShitQuotient: "Rooters of All Evil" and the sheer amount of CerebusRetcon[=s=]. [[spoiler: Kevin is a mutant, not an alien. Max was never his dad's partner and probably didn't even know him, Kevin's real dad was likely not even a Plumber or Osmosian (and thus may still be alive.) The Plumbers kids, and Argit were genetic experiments and pretty much everything stated in Alien Force/Ultimate Alien about any of this was a part of a giant mind control-based false memory.]]
* HoYay:
** With Kevin gone, Rook has become the main character yaoi fangirls can pair up with Ben. Not helped by the fact that 1) he admits himself to be an AscendedFanboy of Ben, 2) he has been revealed to be of a ''[[CatBoy feline species]]'' and 3) he actually seems to dislike Esther when she flirts with Ben...
** Certain episodes are absolutely chock full of homoerotic undertones. Special mention goes to "Bros In Space". For a bit of context, the whole episode revolves around Rook's father not approving of Rook's choices--bringing Ben to Revonnah being among said choices--and as a result, it's overflowing with a "why don't you like my boyfriend" sort of vibe. The cherry on top has to be when Rook snubs Rayona, his ex-girlfriend whom he supposedly still has feelings for, because he "does not yet know the plans of [his] houseguest", AKA Ben.
** Kevin and Rook also get some moments, like their subplot in "Charm School" where they ignore Gwen and Ben to hang out with each other.
** As in the previous series, Gwen seems a bit obsessed with Charmcaster in "Charm School" and tries to get her to see reason. [[spoiler: The nature of the ending to "Third Time's a Charm" also raises some eyebrows, which is Gwen's last scene in Omniverse, where she affectionately pats Charmcasters bag, while telling Kevin she had always wondered if she and Charmcaster could be friends in different circumstances and how she now knew they will be.]]
** Many have pointed out that the episode meant to [[ShipSinking sink Ben/Esther]] and solidify [[HappilyMarried Ben/Kai]] really [[RelationshipWritingFumble made a convincing case for Esther/Kai.]]
** Lucy flirting with Gwen while transformed into Kevin in one flashback episode, which is also ''more'' KissingCousins antics for this franchise!
* HypocriticalFandom : Remember all those plotholes and retcons that made fans cry that ''Alien Force'' and ''Ultimate Alien'' sucked? Yeah? Well don't expect the same fans to complain when ''Omniverse'' does its own even more confusing retcons or makes blatant {{Series Continuity Error}}s; apparently, it's okay if it's against ''AF[=/=]UA''.
* IAmNotShazam: The villain featured in the episode "Trouble Helix" is Malware, ''not'' Helix, despite the name of the episode. Helix is the name of the device that was used to create him.
* IdiotPlot:
** ''Food Around the Corner'' has this big time; as the Plumbers must organise a fragile peace treaty between the Appoplexians and the Ludoans, those only agree to do it if a Galilean (Gravattack's species) presides the conference, as they are known to be wise and patient. Instead of just finding a real Galilean willing to do the deeds, they decide to use ''[[IdiotHero Ben]]'' (who, remember, retains his usual personnality when transformed) as Gravattack. Instead of just having him use the lock-mode function that was introduced in ''Frog of War'' four episodes ago (though Word of God says he doesn't have the codes for it), which he was shown to be perfectly capable of disactivating by himself, they have [[TooDumbToLive Blucik and Driba]] implant him a device that prevents him from turning back to human, which he cannot shut down by himself. And on top of that, they leave Ben to preside the conference alone, without any com-link device or other mean to contact him should something go wrong. The whole sabotage of the conference could have been avoided had they just avoided half of those mistakes.
** The infamous break-up between Ben and Julie, and by extension half the plot of ''Rule of Engagement'', could have never happened if Ben had just been smart enough to call her back immediatly after the video game incident and explain her what happened.
** ''Universe vs. Tennyson'': Where do we begin? First, we have Chadzmuth, a Galvan lawyer, abusing loopholes to get criminals like Fistrick out of jail. Then, Ben is summoned to galactic court for recreating the universe back in ''So Long and Thanks For All the Smoothies''. The trial goes as expected, until Ben himself is summoned to the stand, and asked to taste a grape smoothie. After doing so, Ben breaks down and admits that he had to rebuild the universe, but couldn't get the grape smoothie right. Ben is found guilty, but then abuses a loophole in the system; Tetramands (Four Arm's species) are allowed to fight their accusers, and if they win, they win the case. But there's no rule that states that the Tetramand has to remain a Tetramand, so Ben transforms into Alien X, and after convincing Serena and Bellicus to let him have control for a while, he wins. Serena and Bellicus are then found guilty, and must pay five pieces of Taydenite.
** Almost any episode after ''Universe vs. Tennyson'' is doomed to either become an Idiot Plot or rely on the Omnitrix giving the wrong form to Ben, since Ben has now complete control over [[RealityWarper Alien X]]. Particularly visible in ''Weapon XI'', where he actually uses Alien X [[ConflictBall but chose to make the Amalgam Kids shoot each others instead of just breaking Proctor Servantis' mind control over them]], and in ''Rook Tales'', where he doesn't even consider just using Alien X against Kundo.
* InternetBackdraft: The show in general tends to cause this.
** Kevin's new appearance in this show has garnered a ''lot'' of hatred from Kevin's {{fangirl}}s. In fact, one of them even [[http://fc07.deviantart.net/fs70/f/2012/340/7/2/fans_opinions_about_kevin_new_design_by_silverlady7-d5n8aqp.jpg wrote a list of all insults used by fans to describe said new look.]] And that includes many fans who actually ''like'' ''Omniverse''.
** And let's not even talk about what happened when it turned out Gwen got a ''second'' redesign.
** Ben rebuilding the Universe as Alien X as a justification for all the retcons. The less said about it, the better.
** Surprisingly enough considering [[TheScrappy what was initially]] [[SatelliteLoveInterest thought of the character]], Julie and Ben breaking up caused one. A lot of fans compared it to ''ComicBook/OneMoreDay'' as one of the worst break-ups in fiction.
** Try bringing up the Rooters retcon on a forum discussion, and watch the FlameWar begin.
* ItsTheSameNowItSucks: There have been criticisms about the show reusing ideas or concepts from the original show, resulting in repetitive parts (such as episode whose scripts seems to be ''[[RecycledScript directly based on original show episodes]]'') or ContinuityPorn that doesn't make much sense (cameo of the Kraken, a creature that wasn't portrayed as an alien in its first appearance, as used by space pirate for a watchdog, or a cameo in present of Exoskull, a villain from ''five years in the future at least'').
[[/folder]]

[[folder:J-P]]
* JerkassWoobie:
** [[spoiler:Even though Phil was a bastard in his only original show appearance, ''Omniverse'' revealed that, after surviving for a year in the [[PhantomZone Null Void]], he ended up captured by Malware and Psychobos, used as a test subject for the Nemetrix, sent after Ben, apparently gravely injured due to the Nemetrix being unable to function right with him, and then took by his captor ''again''. When he is finally brought back, it turns out he died and his body ended up controlled by parasites.]]
** Malware ''sort of'' started out as this, but, once Albedo "cured" him, [[SubvertedTrope threw the Woobie part out the window]] uses all his next appearances to [[KickTheDog show us]] [[TheSociopath what a bastard he really is]].
** Ben 23 gets this treatment too. In "Store 23" we first see Ben 23 as ''more'' of a narcissist than the original Ben. Then we learn that [[spoiler: in this universe, Max died before Ben received the Omnitrix. Without Max, there's no CharacterDevelopment that helped the original Ben become the hero he is today and no one by Ben's side. All the money and fame he receives in the universe will never replace family, treating 23 Ben more as a StepfordSmiler.]]
** Hell, the original 11-year old Ben may qualify [[spoiler: when Feedback's DNA is killed right in front of him by Malware.]]
** Even though [[TookALevelInJerkass he is significantly less sympathetic than before]], Albedo ''still'' manages to be this: [[spoiler:[[YankTheDogsChain just when he had finally got his Galvan form back]], [[DesignatedHero Azmuth]] decides to inflict him a petty punishment by not only causing him to lose it again, but turning him into a ''11 years old'' Ben this time]]. The final scene of him [[spoiler:crying at the end of ''For A Few Brains More'']] is played for comedy, but some fans felt genuinely sorry for him at this point.
** Still Charmcaster. She's a Jerkass for doing evil [[spoiler: under the advice of the monster who killed her father, who she arrogantly believes is of no threat to her anymore]], but a Woobie for still recovering from a mental and emotional breakdown while DesperatelyLookingForAPurposeInLife.
* JustHereForGodzilla: Some older fans are Just Here for Rook.
* LikeYouWouldReallyDoIt:
** In "And Then There Were None", [[spoiler:Vilgax destroying all the timelines but the one without an Omnitrix, killing all but one version of Ben Tennyson, including the mainstream one, in the process. Nobody was surprised when it was fixed in the next episode.]]
** [[spoiler:Kevin's FaceHeelTurn]] in "Weapon XI Part 1" left fans skeptical, figuring that after two series of [[spoiler:him being a good guy]], such a thing couldn't, and shouldn't, be done at this point. [[spoiler:So quite a few were unsurprised when Kevin revealed he was faking it.]]
* LoveItOrHateIt: Fans either love ''Omniverse'' for taking the show back to its roots, making many homages to the original show, and giving [[EnsembleDarkhorse Rook]], or hate it for its overly simplified art style, juvenile tone, and decayed Ben.
* LoveToHate: The fans really love Malware (who's easily one of the most vile and despicable villains in the entire franchise) due to him being an terrifyingly awesome and GenreSavvy bad guy with [[TheUnfettered zero moral qualms]]. This made him ''really'' stand out, especially given the new DenserAndWackier approach.
* MagnificentBastard:
** Malware, and to a lesser degree Dr. Psychobos.
** Attea, full stop. [[spoiler:The whole Incursean story arc was a plan from her to take over her Father's throne.]]
** Zs'Skayr in the Galactic Monsters arc, as nearly every episode in the arc ended with him pretty much getting what he wanted without much effort, only [[TookALevelInDumbass fumbling in the finale.]]
** Proctor Servantis, considering just how far and how long his plan spanned.
* MisBlamed: Quite a few fans blame Derrick Wyatt for the DenserAndWackier nature of the show, but this was actually due to ExecutiveMeddling. Since the original series always gets the best ratings while the super-dark ''Ultimate Alien'' got the worst, the execs wanted ''Omniverse'' to go for a tone closer to the first series, making the writers insert a more comedic tone.
* MoralEventHorizon:
** Malware either crossed it either by murdering several Galvanic Mechamorphs in "Trouble Helix" (sure, he needed to feed himself, but he shows no remorse, and is actually mad because [[ItsAllAboutMe Azmuth cures them instead of helping him]]) or by [[spoiler:using Phil as an unwilling test subject]].
** He definitely crossed it in "Malefactor", when he decides to keep Ben from pursuing him by ''[[WouldHurtAChild throwing a tanker truck at a school bus]]''.
** [[spoiler:Ben 23]], of all people, almost crosses it by [[spoiler:attempting to ''rip his dimension's Azmuth in half'']]. He is fortunately stopped before this happens.
** Dr. Psychobos crossed it when he came up with a plan to [[spoiler:assassinate Azmuth and ''commit genocide'' on the entire Galvan species.]]
** If the above didn't count for Malware, helping Psychobos do ''that'' [[spoiler:''to his own species'']] certainly does for him as well.
** Vilgax's CharacterRerailment helps him cross it again when in "And Then There Was None" where [[spoiler:he sets off a bomb that wipes out all universes, save for the one he was in, which happens to contain a Ben Tennyson with no Omnitrix. He's essentially wiped out millions of worlds, so many lives that counting them would be impossible, and his own allies, all so he can murder a powerless Ben]].
** Proctor Servantis crossed this line ''long'' ago when he [[spoiler: decided to turn a group of orphan children into his own personal army of living super-weapons.]] And to make it even worse, all of this was so he could [[spoiler:murder a completely innocent 11 years old kid just because he ''might'' one day become dangerous to the Universe.]]
** Kundo in "Rook Tales" crossed it when he assaulted Rook's father for letting Shar, Rook's sister, leave their world to become a plumber. Before, Rook was extremely hesitant to fight his former teacher, but when he learned what happened to his father he decided the line was crossed.
** Much like with [[spoiler: Ben 23]], "The Color of Monkey" has a character ''almost'' cross the line but get stopped before it happens. In this case, [[spoiler: it's Argit planning on selling a ''baby'' Lewodan (whose parents are worried sick over) to Jarret, who would ''eat it.'' Luckily, Ben out-gambits Argit and the sale never transpires.]]
** Maltruant might have caused some death and destruction during the Time War, but the final episode is where he crosses it. [[spoiler:His plan was to swap the anihilarg that created Ben's universe with one of his own, which would thereby erase Ben and everyone else from existence, to create a universe in his own image]].
* NightmareFuel:
** Zombozo's new, corpse-like design, which, if you look closely, you can see his ''ribs'' and some flesh that appears to be falling off of his body on his face.
** Malware really upped the ante by [[spoiler:[[MoralEventHorizon destroying Galvan B]]]].
** The fifth story arc, subtitled ''Galactic Monsters'', is pretty much guaranteed to be full of this, as if that wasn't obvious by the theme song being modified with a G-Major-esque reverb.
* NightmareRetardant:
** While the concept of a DoomsdayDevice able to destroy the whole universe is quite scary, it's a bit hard to take it seriously when it's called "Anihilarg."
** Trumbipulor tries to invoke NightmareFuel with his robot minions by designing them on the scariest, most threatening-looking creatures he could think of in the galaxy. The problem is, he is afraid of ''mice'', which aren't exactly considered scary by human standards.
** Maltruant actually looks fairly menacing up close... And then it's revealed that he's a Chronosapien (the species that Clockwork hails from), which makes him look fairly comical and awkward.
* NoYay: Attea and [[spoiler:Ben[=/=]Bullfrag]]. Even excluding the {{Squick}} involved by the fact Attea is an Anthropomorphic frog while [[spoiler:Ben is human]], there is the fact that Inkurseans grow faster than humans... meaning [[spoiler:Attea is technically ''a lot'' younger than Ben, which can be seen by Bullfrag looking like an adult rather than a teen.]]
** Also, fans' general reaction to Gwen's [[HotForTeacher newfound crush on Hex.]] Giving a female character a crush on a much older guy who has been stalking her for magical artifacts since she was ten can have this effect.
*** It's also Hex's reaction to [[AbhorrentAdmirer Professor Xagliv]] coming onto him.
** Some fans feel Kai's obsession with Blitzwolfer (and to some extent with Ben's other alien forms in later episodes) has reached a level that stops being funny and starts being rather disturbing.
** "The Most Dangerous Game Show" has Charles Zenith organize a game where girls have to compete to become Ben's wife. In order to do so, he summons every single woman Ben ever met without their consent. This includes several non-humanoid aliens, women who are adult, married or already in relationships, and Ben's ''[[IncestIsRelative relatives]]''. Thanksfully, Ben at least calls out Zenith for the latter and he sends back home all of those who were related to Ben.
* {{Padding}}: In "Frogs of War Part 1", the Randomizer function seems to have been added to the episode just to give a problem to Ben, as it doesn't really add a whole lot to the episode considering Ben's problems and frustrations with the Omnitrix ''already'' (common problems include the time limit's varying length and changing into the wrong alien a lot), and takes up a few minutes in the least. The Omnitrix could have glitched out and there really wouldn't have been much of a difference.
* PanderingToTheBase: The show as a whole is obviously intended to satisfy all the original series ''Ben 10'' fans that complained about ''Alien Force'' and ''Ultimate Alien'' being too different; as a result, we get characters being redesigned to look closer to their original series selves, several characters and elements from the original series coming back (including one-off characters such as the Megawatts), and flashbacks parts and episodes taking place in the original series era. Oh, and Kevin and Gwen are PutOnABus, possibly to satisfy those who complained about RomanticPlotTumor. Well, at least they didn't try to satisfy the [[KissingCousins Bwen]] fans...
[[/folder]]

[[folder:Q-Z]]
* ReplacementScrappy:
** Rook has been initially seen as this to Gwen and Kevin by some fans (though fans who considered Gwen and Kevin [[CreatorsPet Creators' Pets]] and disliked [[RomanticPlotTumor Gwevin]] were a fair bit more accepting of him) before the series came up. By now however, he has become [[EnsembleDarkhorse the opposite]]. It's been said that the reason they were demoted to {{Recurrer}} status was because they were overshadowing Ben. (Then Rook [[HilariousInHindsight comes in and shows us how being cooler than the main character]] is ''really'' done.)
** The New Omnitrix is by now mostly seen by fans as a ReplacementScrappy [[UpToEleven even to the Ultimatrix, which some fans saw as a replacement scrappy by itself]]; This is mostly due to it [[TheyChangedItNowItSucks having a completely different design than all previous variants of the Omnitrix]], [[InformedAbility being hyped up as better and an improvement over both the Prototype Omnitrix and Ultimatrix yet not displaying any actually better features]] and generally being ''awfully'' less practical than its predecessors (in fact, the few functions it displays that weren't present on the previous models only end up making it ''even harder'' to use most of the time).
* RescuedFromTheScrappyHeap:
** Some of the poorly designed aliens from ''Ultimate Alien'', such as Jury Rigg and Eatle, got a bit of this thanks to their new designs. Jury Rigg's aviator suit, especially, made him only more popular.
** Psyphon was considered by a few fans to not be terribly noticeable. His ''Omniverse'' incarnation [[TookALevelInBadass being able to fight Ben on more equal ground more consistently]] and giving him more distinguishable characterization gave him a few more fans.
*** He ended up thrown right back in it with "Bengeance is Mine" and "Cough It Up", unfortunately, in which he very much TookALevelInDumbass.
** When their respective powers were ''finally'' revealed, both Molestache and Pesky Dust turned out to have abilities original and creative enough to at least make them slightly more likable to the fanbase.
** Kai for a good many who disliked her in the Original Series, although [[BaseBreaker she is still heavily divisive,]] [[StrangledByTheRedString particularly after her second appearance.]]
* TheScrappy:
** Many of the comedic new characters such as Hokestar, Blukich, and Driba are usually considered fairly annoying or pointless to the narrative. Doesn't help that, in Blukic and Driba's case, they also are [[CreatorsPet Creator's Pets]] and show signs of FantasticRacism.
** Pax deserves a special mention, being a walking hippie stereotype with AnimalWrongsGroup tendencies whose very existence contradicts the Original Show (where Florauna were portrayed as a feral and carnivorous in ''Secret of the Omnitrix'').
** Harrangue managed to get ''even more'' hatred than he already had in ''Ultimate Alien'' when he ''praised'' the Incurseans for invading Earth and getting rid of Ben.
** The aliens introduced in ''Outbreak'' (namely Walkatrout, Pesky Dust, Molestache and the Worst), due to all four of them having poor designs (the design process was literally just picking some of the preexisting "civilian" background aliens) and being introduced as nothing else than {{Joke Character}}s. Pesky Dust had its powers revealed ''28 episodes later'', Molestache and the Worst ''46'' (And Molestache's was revealed in a deleted scene, with that), and Walkatrout ''never'' did (and according to WordOfGod, his sole power is to ''[[WhatKindOfLamePowerIsHeartAnyway walk]]'').
** While Rad Dudesman wasn't particularly disliked when first introduced, he has started becoming this trope after his portrayal in ''Galactic Monsters'', where he TookALevelInJerkass.
** Collectimus, due to being a very obnoxious character and a blatant TakeThatAudience. Fans, especially those who liked the Alien Force[=/=]Ultimate Alien era, were not amused.
* SeasonalRot:
** The third arc featuring the Incurseans wasn't considered particularly impressive, most likely due to the fact that it comes right after [[ToughActToFollow two arcs featuring a very personal enemy to Ben]], the fact that it tries to (and sort of fails, given the [[{{Flanderization}} increased focus on their frog-like aspects]]) reintroduce the Incurseans as a real threat, being [[DenserAndWackier too goofy, even in comparison to previous episodes and arcs]], and Ben's CharacterRerailment being undone. The ending creating a major [[SeriesContinuityError continuity error]] and [[EsotericHappyEnding how the whole thing is resolved]] didn't help matters.
** While the fourth arc started out promising, it included slightly more fillers than previous arcs (its storyline was only three episodes long and took some time to actually start), and its finale was generally considered very disappointing due to undoing the CharacterRerailment that had been done with [[BigBad Albedo]], an AssPull used to bring back Kevin and Gwen (whereas they had actually credible reasons to be there in the previous finales) and featuring some rather anticlimatic fights. The arc also included episodes where protagonists did rather morally ambiguous actions that placed them in DesignatedHero territory in the eyes of some fans.
** The fifth arc had a tendency to wrap up its conflicts with [[GameBreaker Game Breaking]] aliens, and [[TheyWastedAPerfectlyGoodPlot failed to fully exploit its potentially interesting premise]].
** The finale "Time War" story arc of the series didn't impress overall; despite the name, [[TheyWastedAPerfectlyGoodPlot this "Time War" never actually is featured in the arc]] and only gets a few passing mention as a backstory for the main villain, while the season's story involves Maltruant collecting various [[MacGuffin MacGuffins]] through time with the help of two goons for his [[HiddenAgendaVillain Hidden Agenda]] (which [[spoiler:turns out to be a generic "reshape the Universe in my own image" plan]]), and even ''that'' gets little focus in favor of Ben getting together with Kai in a... [[StrangledByTheRedString not very well-handled manner]]. Maltruant himself is considered by most fans a blatant GenericDoomsdayVillain who would be boring if he wasn't voiced by MarkHamill. In addition, this season featured [[MerchandiseDriven a lot of new gimmicks clearly done for the sake of toy promotion]], most of which were [[BaseBreaker Base Breakers]] at best (Skurd) and [[TheScrappy Scrappies]] at worst (the Time-cycles).
* {{Squick}}:
** Space fleas. Sentient space fleas.
** Zs'kayr's cloak becomes this when you realize that it's not a cloak at all. It's the "skin" that he had when he revealed what he really looked like, meaning that Zs'kayr is wearing his ''own skin'' as a hood.
* StrangledByTheRedString: Invoked with Ben/Kai in "Fight at the Museum", as they barely had ''any'' development in their relationship before being declared true loves [[BecauseDestinySaysSo because Spanner says so.]] It's made quite clear that, while they do love each other in Spanner's future, Ben and Kai barely tolerate each other now. They resent Spanner's attempts to hook them up. To make it worse though, Ester believes YouCantFightFate and leaves Ben and Kai to be together.
* StrawmanHasAPoint:
** Albedo has been established to not give a damn about what others think, and will bend the truth to himself to make sure nothing is his fault. However, it's implied that, at the end of "For A Few Brains More", that Azmuth [[spoiler:''messed with'' Albedo's Omnitrix, forcing him back to a Ben form, and a ''younger'' Ben form at that]], meaning that Albedo just might have some legitimate problems with Azmuth.
** Dr Psychobos indisputably is racist toward Galvans, and his accusations toward them of arrogance is clearly meant to have him appear as a {{Hypocrite}}. However, some comments made by Blukich and Driba about Cerebrocrustaceans suggest that his arguments of Galvan arrogance might have some credence.
* TakeThatScrappy:
** Ben finally gets called out for his arrogance in "Predators and Prey Part 1" by Rook, who can't stand it at this point, a sentiment that many fans have felt since ''Omniverse'' began. While part 2 revealed that it was a charade, he ''seriously meant what he said to Ben about his arrogance''.
** And according to WordOfGod, [[http://www.formspring.me/DerrickJWyatt/q/410836306784971342 he is not too fond of]] [[ReplacementScrappy Fastrack]], which explains the increase of the usage of [=XLR8=].
** Comments from Blucik and Driba indicating that Galvans are smarter than Cerebrocrustaceans ''might'' have been an attempt of this trope to those who considered Brainstorm a ReplacementScrappy to Grey Matter, but it didn't exactly worked as intended; if anything, it made Blucik and Driba look like [[FantasticRacism racists]].
** Probably unintentional, but those amongst the fans who dislike Blucik and Driba might enjoy this part of dialogue from "Store 23":
--->'''Azmuth''': "You two are brilliant scientists."
--->'''Blucik and Driba''': "Oooooooooh!"
--->'''Azmuth''': "By Earth's standards; for a pair of Galvan, you are remarkably unintelligent."
--->'''Blucik and Driba''' (''disappointed''): "Oooooooh...."
** The ShipSinking of Ben/Julie came with Ben unintentionally hurling insults at Julie while playing a video game. The fact that Julie was so unpopular with many of the fandom due to derailment in ''Ultimate Alien'' couldn't be a coincidence.
** Possibly as an answer to fans complaining about him being a KarmaHoudini in ''Ultimate Alien'', Will Harrangue essentially gets everything in the face: Ben "accidentally" sprays him as Water Hazard in ''Frogs of War'', he starts losing viewers after siding with the Inkurseans during their invasion, and [[spoiler:a vengeful Jury Rigg [[KarmicTransformation mutates him into a tentacled alien]].]]
** Many fans disliked the ''Ultimate Alien'' episode "Couples Retreat" due to [[{{Jerkass}} Darkstar]] taking advantage of [[WoobieDestroyerOfWorlds Charmcaster]] [[KickThemWhileTheyAreDown immediately after she'd already suffered from crossing the]] DespairEventHorizon. [[spoiler: The ending to "Mystery Incorporeal", in which Charmcaster appears to have some fun torturing Darkstar for messing with her realm, pleased these fans greatly.]]
* TearJerker:
** The reason why Ben doesn't use Feedback anymore was intended to be one. Not everybody was convinced by it though. See {{Narm}} for more details.
** In ''Store 23'', [[spoiler:Ben 23 snapping and finally admitting he does miss his Dimension's Grandpa Max.]]
* TheyChangedItNowItSucks:
** Oh so much, for any given subject. The artstyle is the most frequently listed exemple, but there are many, ''many'' more.
** A special mention has to go for ''T.G.I.S.'', the crossover episode with ''WesternAnimation/TheSecretSaturdays''; the Saturdays were completely redesigned to fit the TimeSkip and Omniverse artstyle, leading to some changes that weren't necessarily well-received by the series' fans.
** InUniverse, Collectimus says he prefers the old version of Mr. Smoothy to the new one.
** Another special case worth mentioning with Zs'Skayr; even those who found his portrayal in this series satisfying generally agree turning right-side up his iconic upside-down skull was a stupid move.
* TheyWastedAPerfectlyGoodCharacter:
** Gravattack is the only one of the new aliens that can do something ''none'' of Ben's aliens could do before; he also is one of the least used aliens so far. Possibly a JustifiedTrope; Gravattack is just too powerful to be regularly used due to [[StoryBreakerPower the nature of his gravity alteration powers]].
** The Vreedle Brothers; after the CharacterDevelopment they got in UltimateAlien and their HeelFaceTurn, the writers decided that they were better as villains and just had them blow up the Plumber Academy before being back to being Con Men. Especially annoying in that this was totally unnecessary: if they wanted villainous Vreedle Brothers, they could have just used a separate pair of clones that were still criminals, seeing how ''Con of Rath'' etablished there were an army of them.
** Speaking of CharacterDevelopment and HeelFaceTurn undoing, what's been said about Charmcaster's eventual appearance in the series has NOT been received very well by those who liked what the previous show was doing with her. Dwayne [=McDuffie=] [[WordOfGod claimed she was one of his favorite characters]]; and he named her "Hope" and had her caught in the neutral zone of the HeelFaceRevolvingDoor following her DespairEventHorizon for a reason. [[AbortedArc But that seems like it might be forgotten about]] [[AuthorExistenceFailure now that he's gone.]]
*** A possible subversion, as what Derrick Wyatt had in mind for her was apparently overruled by other writers on the staff and Charmcaster remained a gray-shaded AntiVillain stuck in the HeelFaceRevolvingDoor instead of just a baddie. It may still count as a waste for some since the redemption arc remained canned (even her true MeaningfulName has been written out) and she makes no progress past where she's at, but it's better than a full regression into regular unsympathetic evil in any case.
** Also, when Albedo absorbs Azmuth's intelligence in ''For A Few Brains More'', [[spoiler: he has a HeelRealization about the Universe and seems about to redeem himself. Instead of using this to make his character evolve and have him do the right thing, they had Ben seize the opportunity to trick him and ended the conflict with a fight so Ben could show off his new alien Atomix.]]
** Did you think the prospect of Phil redeeming himself sounded interesting? [[spoiler: Too bad, it turns out that Phil was actually killed from the inside out long ago and a parasite has taken his body and had only been pretending to be TheAtoner.]] Combined with the Vreedles, Charmcaster, and Albedo examples above, many fans at this point are getting sick of Kevin being the ''only'' villain to be allowed a HeelFaceTurn.
** Julie was starting to get better as a character and had been RescuedFromTheScrappyHeap thanks to both CharacterDevelopment and the fact she TookALevelInBadass. Instead of keeping going this way with her in order to improve her again, the writers decide to have Ben and her break up off-screen (with the break-up being shown as a gag in a flashback; he ''accidentally'' broke up with her while playing a video game and having her mistake his shouts at the screen as being at her. They haven't spoken since, and Ben never gave it much thought due to TookALevelInDumbass and TookALevelInJerkass.) and introduce [[UnwantedHarem several new characters as Ben's potential love interest]]. The final nail in the coffin? WordOfGod is that ''Omniverse'' will go to 80 episodes now...and there are no plans for Julie to appear in ''any'' of these planned episodes at all. She's been PutOnABus, quite possibly for good.
** Also, Elena Validus has been confirmed to have a non-speaking cameo coming up and that's it. And it will be as Elena, not as the Hive Queen, meaning she was cured of her condition and her problems from the previous series were resolved ''completely off-screen'': another case of AbortedArc due to Dwayne [=McDuffie's=] AuthorExistenceFailure.
*** It has since been announced that [[AuthorsSavingThrow there will be a graphic novel]] [[AllThereInTheManual that will explain]] what happened between her last appearance in ''UA'' and her cameo in ''Omniverse''.
** Many fans of the horror-themed Anur aliens were excited at the news of the [[OurVampiresAreDifferent Vladats]] (a species which so far had [[AllThereInTheManual only been mentioned in trivia and the Transylians' official bio]]) finally making an appearance in the show, even if only one such character was announced. When said character, Lord Transyl, finally arrived, [[spoiler:he only was there for one episode before being [[AntiClimaxBoss quite easily defeated and disposed of]]]]. Moreover, his powers and personality turned out to be rather generic and bland.
** The Evil Alternate Bens in the "And Then There Was Ben" two-parter just barely get enough time to showcase their base personality traits, but they're otherwise just thugs for Vilgax and Eon. Mad Ben is an exception, as he gets a two-parter dedicated to him and his world at the end of the seventh arc.
** Much like in ''Ultimate Alien'', [[spoiler:Eon being an alternate Ben]] is completely glossed over with no attempt to develop [[spoiler:how Ben became Eon in the first place.]]
** Maltruant; the character is an evil [[TimeMaster Chronosapiens]], is stated to have a connection with a Time War, and on top of that, he is voiced by Creator/MarkHamill. Yet he has absolutely no backstory, no explanation for ''why'' he turned rogue and the Time War he apparently was part of is never explained or elaborated upon, making him come up as a very bland GenericDoomsdayVillain whose voice actor is the sole saving grace. Especially disappointing when you consider he is the series' TrueFinalBoss.
** Ken Tennyson, Ben 10,000's son with his own Omnitrix and a major EnsembleDarkhorse, ''finally'' comes back after being absent for two sequels... [[spoiler:and not only do we find out [[BroughtDownToNormal his parents took his Omnitrix because he was grounded (and he never recovers it for the entire show)]], but he spends most of his appearances in the disguise of time-travelling Spanner, who despite a lot of build-up ends up accomplishing nothing really relevant to the plot. We don't even ''know'' it's him until his final episode ([[TheUntwist not that fans didn't guess]]), so from the viewer's perspective, he only appears as his actual self in ''two'' episodes, one where he only make a silent cameo.]]
* TheyWastedAPerfectlyGoodPlot:
** "So Long and Thanks for the Smoothies" involves Ben and Rook trying to prevent a DoomsdayDevice from falling into the wrong hands, and ends with Ben using Alien X to rebuild the universe. A lot of fans feel the whole thing would have been much better as a serious series finale, or if at least the characters had to deal with the changes caused by such a major event ('' la'' ComicBook/InfiniteCrisis). Instead, we get a random comical episode that has seemingly few to no impact on the story. The only change made was a new design for the Mr. Smoothy store that Ben loves to visit and that it "doesn't taste the same." However, many have assumed that the changes to characters and the changes to canon [[WordOfGod thus far only discussed in interviews]] are because of it. That would make ''much'' sense but so far it's been... well, a perfectly good idea that's been wasted.
** As of "Showdown, Part 1," Psychobos and Malware's plans for the Nemetrix amounted to using it as a glorified distraction. Khyber alone has it now, but as far as the other two's purpose for it, it's largely disappointing. As a matter of fact, Malware is able to pull out his plan of his own ''without using the Nemetrix a single time'', making you wonder why they worked so hard during five years to complete it when just recruiting bounty hunters or killers to distract Azmuth would have worked just as fine.
** In "Showdown Part 1", they introduce the natural predator of the Galvans. Due to its avian nature, some fans believe that it should have been a peacock, using Ben's fear of them to it's advantage. It wasn't.
** Khyber hacking the Plumbers' database for information about Malware in "Trouble Helix", as well as the fact he helps Ben and Rook in "Malefactor" suggested he was a DragonWithAnAgenda who intended to conspire against Malware at some point. This is never brought up in later episodes, or at least not farther than him being obsessed with getting Ben as a trophy.
*** Talking about Khyber, it had been suggested in previous episode that he actually [[EvenEvilHasLovedOnes cared for his pet]], a theory fans liked to support. The writers apparently feared this would lead to DracoInLeatherPants, so they had Khyber [[YouHaveOutlivedYourUsefulness leaving]] [[KickTheDog said pet behind]] in the finale, despite the fact it was entirely against his advantage (see WhatAnIdiot below), completely dropping the idea.
** "Showdown Part 2" has the protagonists of all four series ([[TheHero Ben]], [[BadassGrandpa Max]], [[MagicalGirl Gwen]], [[TheAtoner Kevin]], and [[HypercompetentSidekick Rook]]) coming back and teaming up altogether to stop Malware. How do they do so? By splitting up immediately for various tasks, with Ben fighting Malware alone, Rook and Gwen merely acting as pilots and assistant to Azmuth, Max helping Blucik and Driba to repair a station (by giving up his beltbuckle, no less), and Kevin doing absolutely ''nothing'', instead just having a short subplot where he befriends Khyber's pet. In the end, we don't get any stand of all of them against Malware, who Ben defeats on his own, with the sole help of the Galvanic Mechamorphs and Azmuth. Talk about making Ben's friends even more useless in a fight than they were in ''Alien Force''...
** The show establishes that aliens are a well-known fact among the public, and that they can walk among the populace peacefully. This could have been potentially used to develop issue about FantasticRacism and how the population is adapting to this. However, the story usually doesn't do anything with the idea, usually just showcasing Ben's interactions and treating everything as if nothing's changed. The lack of use of this idea may have even resulted in [[SeriesContinuityError a particularly bad, somewhat grating continuity error]], where "The Frogs of War" reveals them to the human race for the first time, despite previous episodes, seasons, and series contradicting this as Earth has been attacked by aliens several times now.
** The flashback in "Showdown Part 1" implies that Ben's love of Feedback might be caused by some [[PowerHigh sort of addiction to the form]], to the point Azmuth actually moves to Earth to warn him about it. This idea is used only as an excuse to get Ben angry so he will [[spoiler:lose Feedback to Malware]] a few seconds later, and is never brought back again, even after Ben [[spoiler:got Feedback back]].
** The very premise of the show: having Ben playing a BigBrotherMentor role toward Rook could have been a genuinely interesting development for the character, not to mention a logical follow up to his evolution over the course of the previous shows. The problem is, he TookALevelInDumbass and acts more immature than ever, making Rook appears as a HypercompetentSidekick who actually is much more mature than him, so the whole point is lost.
** ''Malefactor'' had Malware absorbing a weapon known as the Tachyon cannon, stated to be able to "rip life forms apart on a molecular level". Such a thing would have been perfect to justify him later [[spoiler:being able to destroy Feedback]]. However, the Tachyon cannon is never mentionned again after this episode, and [[spoiler:Malware instead destroy Feedback with [[NewPowersAsThePlotDemands a new ability]] [[AssPull he pretty much pulls out of his ass]].]]
** When it was revealed the ''Galactic Monsters'' story arc would have Ben travel to the Anur system, many fans were enthusiastic about seeing the various planets and their inhabitants. In the end, the arc chosed to focus on only ''one'' planet (Anur Transyl), ignoring all the other planets in the system and treating Transyl like if it was the home planet for all the Anur aliens. Their culture was also barely explored in favor of portraying Anur Transyl as a stereotypical {{Halloweentown}}.
** "Universe VS Tennyson" wastes a Celestialsapien smackdown, something that could have been Anime/GurrenLagann levels of {{Badass}}, in favor of focusing on a comedic trial against Ben.
** The Time War arc doesn't go into much, if any, detail about what the war was even about, nobody particularly seems to participate in it onscreen. Instead it's more of a backdrop to justify Maltruant's existence.
* TooCoolToLive: [[spoiler:Malware.]]
* ToughActToFollow: One major downside about Malware being an EnsembleDarkhorse is that he was such a great villain he made every single BigBad following him look pale by comparison. His two immediate successors ([[DaddysLittleVillain Attea]] and [[EvilTwin Albedo]]) were former minor villains promoted to [[BigBad Big Bads]] with comical quirks (in contrast with him being a KnightOfCerebus with a major case of VileVillainSaccharineShow), and even a more iconic villain such as Zs'Skayr couldn't compare thanks to his arc being ridiculously short and wrapped up very anti-climatically. Vilgax in the following two-parter and the Rooters in the next arc do seem to have upped the stakes, but the former only last two episode while the latter is a BaseBreaker at best.
* UglyCute:
** The female [=WayBad=] from ''"The Frogs of War"''.
** Much of the Nemetrix aliens. Namely, Mucilator, who more or less looks like a giant dog with weird purple sacs. It somehow manages to be ''adorable''.
* UncannyValley:
** Fistina's face in "Special Delivery" when she gets a date. Seriously.
** Played with in regards to [[spoiler:[[WesternAnimation/TheSecretSaturdays V.V. Argost]]]]. He's, like everyone else in the show, stylized and exaggerated, but his mask has a surprisingly distinct, "fake" look to it.
* TheUntwist:
** Wait, so [[spoiler:Lucy ''wasn't'' the spy]]? [[SarcasmMode What a surprise]]! After all, it's not like if any GenreSavvy viewer would have easily identified her as an obvious RedHerring, especially [[spoiler:since Gwen had next to no reason to suspect her beside her petty dislike of her]]...
** Kevin [[spoiler:being a FakeDefector]] at the end of ''Weapon XI''. The way he [[spoiler:suddenly was convinced into making a FaceHeelTurn by Proctor Servantis]] felt so forced, some fans suspected right away [[spoiler:he was only pretending to believe the Rooters]].
** Spanner's reveal as [[spoiler: Ken Tenyson]], most had already guessed who it was on his first appearance and as time went on evidence had piled up so much that the only twist would have been if it was someone else.
* VillainSue: Ma Vreedle, despite being a ''comedic'' villain, has received accusations of this from some fans, due to [[CharacterShilling being constantly hyped up as]] [[TheDreaded a fearsome villain who terrorizes everybody]], even though what she is actually seen doing usually doesn't really seem worse than what many minor villains in this show do, being a KarmaHoudini in all her appearance so far in this show, and somehow capable of scaring [[BigBad Vilgax]] (who usually is the one owning the title of most feared being in this Universe).
* WhatAnIdiot:
** If you think about it, Khyber really didn't need to leave his pet behind when he escaped in "Showdown Part 1"; since the Nemetrix works only on non-intelligent beings, that means he will have to find a new pet to replace it and train it to obey him. Moreover, Azmuth would have used the pet to track him had Malware not distracted them.
** Yeah, Dr. Psychobos, we know you are a genius, but do you seriously believe the shapeshifting kid who saved the universe a billion times isn't a threat to your plans?
*** You ''really'' don't want to [[BullyingADragon push your dragon around]] when said dragon is ''[[EgomaniacHunter Khyber]]''.
** Almost ''everything'' [[TooDumbToLive Blucik and Driba]] do enters in that territory, the cake probably being when they leave their duties to go look for a Mr Smoothie while the Plumbers are in the middle of a crisis.
** Ben treats putting Vilgax in Incarcecon rather casually. He's survived several incidents where he was supposed to be dead and has come closest to getting the Omnitrix. As pointed out by Max, Ben should be the first to know Vilgax is not to be underestimated. [[spoiler:Ben ultimately pays for this at the end of the episode, where Vilgax gets away.]]
*** [[spoiler: Though this may be partially justified [[VillainDecay due to how he was in]] ''[[WesternAnimation/Ben10AlienForce Alien Force.]]'' [[TookALevelInBadass Though, one then wonders why he was so casual about it]] [[WesternAnimation/Ben10UltimateAlien when one remembers what]] [[DidYouJustScamCthulhu happened the last time he met with him.]]]]
** The very reason Ben broke up with Julie is because of Ben's sheer stupidity. Seriously, what kind of complete moron would keep playing video game while his girlfriend is talking to him at the phone?
*** If that wasn't bad enough, Ben never ''once'' considers to call her when she stops contacting him after the event, yet still considers Julie to be his girlfriend as of "Rules of Engagement." That's... [[Series/StarTrekTheOriginalSeries illogical]], to put it lightly.
** In ''Frogs of War'', Kevin, Gwen, Rook and Blucick trusted ''[[ChronicBackstabbingDisorder Argit]]'' in their rebellion. This goes as well as you'd expect.
** In ''Return to Forever'', Ben tries to chase Sir Morton, who kidnapped Jimmy Jones. You'd expect him to just transform in [=XLR8=], Fasttrack or Jetray and easily catch up. But of course, we need Rook to be of some use, so he just runs in human form and eventually gives up to jump in Rook's vehicule.
** Also in ''Return to Forever'', Ben as Lodestar is fighting the Forever Ninja, which is a robot. Rather than using his magnetic powers directly on his metal opponent or even the metal vehicles they're both standing next to, he only tries to use them on the shurikens that are being thrown at him. When the shurikens turn out to be wood and he can't control them, the Forever Ninja is able to completely hold Ben at bay.
** The Plumbers in ''Mud Thicker Than Water'' for [[spoiler:allowing Gorvan, a ''renegade Plumber'' (it's hinted he already fought with Ben and Gwen before in this continuity, so his backstory from the Alien Force game is still most likely canon) to still be part of them. Even assuming they didn't know who he was, you got to wonder why they never questionned the fact one of their member never removed his suit.]]
** For the matter, they also [[spoiler:chose to keep and move ''[[DoomsdayDevice the Anihilarg]]'' after Blucick and Driba fixed it, instead of just destroying it again and dispose of the pieces. No justification is given to explain why they would want to keep it ([[FridgeLogic why would anyone want to have such a device if they can't use it without destroying themselves with it, anyway?]]), and it has been proven in ''So Long And Thanks for the Smoothies'' that destroying it is both easy and without backfire.]] For added stupidity, [[spoiler:it's revealed in ''End of an Era'' that they ''still'' are keeping it in the future, implying ''they never considered the possibility to destroy even after Ben grew into an adult'']].
** Azmuth isn't an idiot, but you still have to wonder what he was thinking when he came up with the "randomizer", a function that causes the Omnitrix to uncontrollably turn its owner into random aliens and basically serves no purpose other than make it even more difficult to use.
** In ''A Fistful of Brain'', Ben is trapped in Albedo's and Khyber's hideout, in a death game with Khyber chasing him. To run away from him, Ben turns into Ditto, reasonning Khyber won't be able to chase them all at once... Except the Original show made it very clear that if one of Ditto's clone is killed, all the others will die as well. Meaning this choice of transformation is a perfect way of making things ''easier'' for Khyber.
*** This weakness was retconned, as detailed on the Ben 10 Omnitrix Aliens character page.
** Ben is told at the end of ''A For a Few Brains More'' by Azmuth that the reason the Omnitrix keeps giving him the wrong alien is because he is pushing too hard. In the next story arc, he is supposed to know that, yet ''keeps pushing just as hard'', despite supposely knowing it will get him the wrong aliens.
** In ''Mystery Incorporeal'', Ben, Rook and Kevin comes to suspect professor Xagliv is Vilgax in disguise, under the sole justification her name is "Vilgax" backward, [[FridgeLogic despite the fact the real Vilgax is around four times her size, isn't known to possess any ability to shapeshift and usually operate through large-scale invasions rather than infiltrations]]. Not only that, but they decide to confront Xagliv in person, without any real proof to back up what they say, and brutally interrogate her. Needless to say, her reaction isn't good when it turns out she ''isn't'' Vilgax.
** When Ben asks Future!Animo to explain what his new alien Gutrot does, Future!Animo goes ahead an explains it to him, in spite of the objections of his present day self, allowing Ben to near-effortlessly beat them. What's odd about this is that it reverses the characterization the two Animos had had throughout the episode; present day Animo had been the bumbling insane one, while Future!Animo had been competent and intelligent.
** Ben, transformed into Swampfire, an alien that can control plants, being attacked by a horde of plants, does not attempt to control the plants. Only when his PubertySuperpower gives him the new ability to control them ''without trying'' is this obvious solution reached.
** Zs'Skayr, for coming up with a plan involving resurrecting the extinct [[OurVampiresAreDifferent Vlatats]] as his army, without ''[[GenreBlind any means]]'' [[EvilIsNotAToy to ensure he will be able to keep an horde of]] [[FantasticRacism racist]], [[HorrorHunger life force-starving]], [[MindControl crowd-enslaving]] monsters under control, when he could barely ''convince'' their leader alone to work with him. For added stupidity, his own [[TheDragon Dragon]] is from a species who used to be enslaved by the Vladats, and [[spoiler:he ''still'' fails to see any betrayal coming]].
** According to WordofGod, every time Ben gets the wrong alien it's simply because he selected the wrong one or is being so rough with the device that it is malfunctioning. This is understandable when he's cycling through 50+ aliens under time pressure, but in situations where time is not a factor or when alien selection is particularly important, Ben's repeated failure to turn into what he wants veers into severe IdiotHero territory. The most egregious example so far is in ''Catfight,'' where HarmlessVillain Nyancy-Chan was neither running away nor attacking, but Ben still couldn't be bothered to be careful enough to avoid selecting the ''one'' alien he had that was vulnerable to her MindControl.
* WTHCastingAgency:
** In a nutshell, any time they bring back an old alien but find a new voice actor to play him. We got this to some degree with AF and UA, with DeeBradleyBaker voicing ''all'' of Ben's aliens old and new save Rath, but ''he'' is a ManOfAThousandVoices whose portrayal is such that you'll hardly notice. The new ones will make you say "What do you ''mean'' that's supposed to be Cannonbolt?!" However, a lot of the new voices are quite ''appropriate,'' such as [=XLR8=]'s accelerated speech.
** This is definitely in effect for fans of ''WesternAnimation/TheSecretSaturdays'' as many people reacted negatively to the fact that the titular family were voiced by different voice actors in "T.G.I.S." than in the series proper.
*** However, this is somewhat justified in Zak's case. T.G.I.S. takes place three years after ''TheSecretSaturdays'' ended. Zak was thirteen at the end of his series but he's sixteen here. (The Saturdays went through a three year time skip, according to Animo and Argost anyway.)
* WinBackTheCrowd: The show has been trying to recapture the magic of the first series. [[BrokenBase Reactions have varied.]] [[InternetBackdraft They have varied a lot.]]
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