* DesignatedHero: George and Harold have a tendency to slip into this with some of their pranks. In the first book, they cause enough disruption at a school football game to get the school to forfeit it, and subsequently ruin everyone else's day, and Captain Underpants is later created as a result of their attempt to avoid being punished for this. In the second book, they sabotage the school's Invention Convention out of spite, due to them not being allowed to attend following the prank they pulled last year. And in exchange for fixing all the damage done by the villains, they have Mr. Krupp cancel their punishment and let them run the school for the day, during which they sell a lot of the staff's furniture to pay for the party they throw for all of the students. Granted, they do try and stop the villains in every book, but the fact that many of them (the Talking Toilets, Poopypants, Wedgie Woman) appear as a result of George and Harold's actions doesn't help their case.
** Granted, there were unordinary circumstances. Poopypants/Tinkletrousers was eventualy going to crack and the fact it happened at Harold and George's school kinda puts it in debate. With Wedgie Woman, they were unaware of the fact that the Hypno ring has reverse effects on women.
** These only apply to the first five books. As the books continue, we see more outside threats not by them or by reoccurring villains (the latest book bringing back the Turbo Toliet.)
* 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.
* 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.
* {{Moe}}: Kindergardener!George and Harold.
* MemeticMutation: The [[http://knowyourmeme.com/memes/melvin-comicsfcking-melvin Fucking Melvin]] RageComics, which are likely based on Melvin Sneedly.
* NauseaFuel: Inevitable in ToiletHumour-themed series, but the Bionic Booger Boy gets special mention. His descriptive introduction is cut off when George yells at the narrator for making everyone sick.
* NightmareFuel: The giant man-eating dandelion in Book 3.
** [[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.]]
* TheScrappy: Melvin and some of the adults at Jerome Horwitz Elementary are this to a lot of fans.
* {{Squick}}:
** A grown man runs around in his underwear with two ten-year-old boys. Okay, ItMakesSenseInContext, but still...
** 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...
* TearJerker: [[spoiler: The ending of the 9th book was REALLY sad.]]
** [[spoiler:Book nine reveals that Harold's father walked out on the family when he was six, and Harold created the Captain Underpants comics as a coping mechanism. Mr. Krupp in his Captain Underpants identity is a kind of Bumbling Dad Parental Substitute for both of the boys, but particularly Harold...]]
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