History YMMV / CaptainUnderpants

* CrossesTheLineTwice: Teachers abusing their kids isn't funny in theory, but when said abuse involves stealing their lunches and making them write lines like "I'm so ugly, when I was born, the doctor slapped my mom", it becomes hard not to laugh.

* DesignatedVillain: Melvin's role in book 2. George and Harold ruin every student's science fair project as a "prank." Melvin witnessed them do this, but George and Harold essentially bribed him by saying that if he kept his mouth shut, they wouldn't mess with his project. Although they do keep their promise, the science fair is ruined and the entire school is left miserable and covered in various disgusting gunk, and Melvin rats out George and Harold to Mr. Krupp after seeing just how much of a disaster it turned out to be. However, it's intended that ''Melvin'' is the jerk in this scenario. George and Harold never face any sort of legitimate repercussions for what they did, and at the end George and Harold exclude Melvin from their party and force him to do a WritingLines of "I will not be a tattletale" instead.

* DesignatedVillain: Melvin's role in book 2. George and Harold ruin every student's science fair project as a "prank." Melvin witnessed them do this, but George and Harold essentially bribed him by saying that if he kept his mouth shut, they wouldn't mess with his project. Although they do keep their promise, the science fair is ruined and the entire school is left miserable and covered in various disgusting gunk, and Melvin rats out George and Harold to Mr. Krupp after seeing just how much of a disaster it turned out to be. However, it's intended that ''Melvin'' is the jerk in this scenario, and at the end George and Harold exclude him from their party and force him to do a WritingLines of "I will not be a tattletale", with George and Harold never facing any sort of legitimate repercussions for what they did.

* ItWasHisSled: Thanks to the internet, there's no hiding the fact that [[spoiler:Harold is gay]] in the 12th book.

* ContinuityLockout: The first five books are pretty much just their own story, and (partially thanks to the {{Infodump}} comic book supplied at the start of each book, can pretty much be read in any order. The series serialization started with book six, but (again, thanks to the comic books) you can probably make it to book eight and still understand what's going on. But after that point, the series plot line becomes so convoluted with multiple timelines and critical plot points based off previous books, that if you try to start the series there, you'd probably be lost even ''with'' the comic books.

** “Stage Floof” for [[spoiler:Future Harold and his husband Billy]].
** “Written Symphony” for [[spoiler:Future George and his wife Lisa]].

* MoralEventHorizon: Tiny Tippy steps close to the line when he [[spoiler: becomes Supa Mega Tippy and leaves Slightly Younger Tiny Tippy in the future]], and eventually crosses it when he [[spoiler: steals Captain Underpants from Big Tippy and leaves the latter to get blown up by his own bomb.]]

** [[spoiler: The BadFuture created by Tippy Tinkletrousers. On top of this disaster-layer cake, we also saw gigantic zombie nerd-versions of George and Harold. Also from this section of the book, Tippy is crushed, blood and all. Doubles as a TearJerker. Thankfully, the last bit (Tippy's death) is averted in the sequel, and it's revealed that the thing that got crushed was a giant ketchup packet.]]

** Taken UpToEleven in (appropriately enough) Book 11, where the boys convince all of the teachers and faculty that they're in a dream. This prompts the grownups to release their inhibitions by performing all sorts of shenanigans ''in their underwear.'' And yes, Dav Pilkey illustrates this repeatedly...

* For that matter, the song "Saturday" by Cold War Kids, recorded for the movie, is also a total bop.

** [[spoiler: The BadFuture created by Tippy Tinkletrousers. On top of this disaster-layer cake, we also saw gigantic zombie nerd-versions of George and Harold. Also from this section of the book, Tippy is crushed, blood and all. Doubles as a TearJerker.]]

* FridgeBrilliance:
** Book 12 received a lot of praise for revealing that [[spoiler: Future Harold]] is gay without making a big deal about it. [[spoiler: Future George meanwhile has a wife that is only ever referred to as "Mrs. Beard"[[note]]Dav later confirmed that said wife was actually named "Lisa"[[/note]]. "TheBeard" of course is a term referring to a woman that has married a gay man.]] [[AlternateCharacterInterpretation Have fun with that, fanfic writers!]]
** The fact that women do the opposite of the instructed by the ring would make a lot of sense if it was an intentional feature because the makers believed AllMenArePerverts, but when they realized that sort of behavior can't be tied down to one gender, and so they recalled it and didn't mention it, or if it did they called it a "mistake", because they realized that feature was a huge failure in design.
** In the fourth book, when Harold tells Captain Underpants to change his name because Poopypants says so, the Waistband Warrior insists that he "doesn't take orders from anybody", but is immediately quick to take an order from George. This might be HypocriticalHumor, or a SugarWiki/MomentOfAwesome proving how loyal he is to his allies, but doesn't let his enemies push him around. However, keep in mind that when George and Harold first hypnotized Mr. Krupp, they told him to obey their every command.
** Professor Poopypants in the books has no clear accent when speaking, but the movie adaptation gives him a [[HerrDoktor heavy German accent]]. Given his country of birth is given as "New Swissland," depending on how close the country is to Switzerland (ridiculous names aside), it's likely that Poopypants would've grown up with some level of fluency in a Swiss German dialect.
* FridgeHorror: A few with the 3-D Hypno-Ring:
** For starters, it's a ''consumer-level MindControlDevice''. All you have to do is trick or force the poor victim into looking at it for a few seconds and snap. JustThinkOfThePotential...
** In ''Wrath of the Wicked Wedgie Woman'', it's revealed that the ring was recalled because for unknown reasons, it worked the opposite of its wielder's intentions on women. UnfortunateImplications aside, this might seem like jumping the gun to younger readers, but George and Harold used it on their already-SadistTeacher and [[GoneHorriblyWrong look what happened]]. Now, what about all the other kids who had one? Chances are, the first thing a lot of them would use it on is their parents, who they typically have a [[AdultsAreUseless very low opinion of]]. All of a sudden, there'd be an outbreak of [[AbusiveParents Abusive Mothers]] all across the country because the kids demand that their every whim be catered to. That wouldn't go unnoticed and would be a pretty damn good reason to recall them.

* MisaimedFandom: Some people tend to paint George and Harold as [[DesignatedHero Designated Heroes]] for their constant pranking, and them getting into trouble for it as LaserGuidedKarma. However, when you take a look at the people that George and Harold prank, they don't come off as better than George and Harold when they retaliate. It has been shown that since they were kindergartners, they use their pranking methods to fight off bullies like Kipper and his gang, and practically the entire staff of Jerome Horwitz Elementary are all bullies to the students. Plus, when George and Harold face the consequences for their pranks, their punishments come off as less of LaserGuidedKarma and more of DisproportionateRetribution like when Mr. Krupp blackmails them into becoming his slaves in the first book, and when he decided to cancel final exams to ensure that one of them will be held back and the other to move on to the next grade to split their friendship apart. Honestly, even if George and Harold deserve to be punished for their constant pranking, the chances of anyone not sympathizing with them when they do get punished are slim to none.

* AerithAndBob: The aliens in the third book are called Zorx, Klax and Jennifer.

* AVillainNamedZrg: The aliens in the third book are called Zorx, Klax and [[AerithAndBob Jennifer]].

* JerkassWoobie: Professor Poopypants. He just wanted people to stop laughing at his name, though George and Harold point out that he could have simply changed it rather than forcing everyone else to change their name into something ridiculous.

** The children affected by the Rid-O-Kid 2000.

** In-universe (and out for the readers)in Book 6. The Narrator's description of Melvin gets grosser and grosser until George [[BreakingTheFourthWall yells at the Narrator to stop]].

** When Crackers's eggs hatch and the creatures inside are half-hamster. Harold imagines different scenarios that could lead to the possibility of [[HotSkittyOnWailordAction a bionic hamster mating with a prehistoric reptile]], but George can only say "EEWWWWWWWWWW!"

* SomeAnvilsNeedToBeDropped: Kids deserve the right to have fun, exercise their imaginations, and enjoy their childhoods without being bullied by adults.

* MemeticMutation: [[Memes/CaptainUnderpants Has its own page.]]

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* NauseaFuel: At one point in ''Ook and Gluk'', Lily ends up barfing directly into the mouth of one of the villains.
* UnfortunateImplications: The Asian characters in ''Ook and Gluk'' are both little more than caricatures; Master Wong is a stereotypical proverb-spouting elderly [[AllAsiansKnowMartialArts kung-fu]] master, his daughter Lan has no real personality outside of [[MightyWhiteyAndMellowYellow being the love interest for Gluk]], and both of them have [[EyesAlwaysShut dashes for eyes]]. Dav Pilkey himself recognized this, apologized, and [[https://www.nytimes.com/2021/03/28/books/dav-pilkey-ook-gluk-racism.html pulled the book from publication]] in the wake of increased hate crimes against Asian-Americans in early 2021.

** The fact that women do the opposite of the instructed by the ring would make a lot of sense if it was an intentional feature because the makers believed AllMenArePerverts, but when they realized that sort of behavior [[RealityEnsues can't be tied down to one gender]], and so they recalled it and didn't mention it, or if it did they called it a "mistake", because they realized that feature was a huge failure in design.

* SugarWiki/HeartwarmingMoments: [[WordOfGod Dav Pilkey]] revealed that while Mr. and Mrs. Sneedly are [[{{Workaholic}} constantly busy with their work]] (to the point of coming across as somewhat [[ParentalNeglect neglectful of their son]]), they actually ''do'' try their best to be GoodParents when it comes to Melvin.

** In-universe (and out for the readers)in Book 6. The Narrator's description of Melvin gets grosser and grosser until George [[BreakingTheFourthWall yells at the Narrator to stop]]