The main antagonist in 'The Adventures of Captain Underpants' is Professor Poopypants—yes, that’s his actual name, and it’s as ridiculous as it sounds! He’s this hilariously over-the-top villain with a name that makes you snort-laugh every time you say it. Professor Poopypants is a mad scientist who’s obsessed with forcing everyone to adopt silly names because he’s sick of people mocking his own. His whole shtick is about revenge through absurdity, which fits perfectly with the book’s goofy tone.
What’s extra fun about him is how Dav Pilkey leans into the childish humor. The guy invents gadgets like the 'Goosy-Grow 4000' to turn people into giant babies and the 'Tippy-Tinkle 2000' to make everyone lose control of their bladders. It’s pure, unfiltered kid-logic villainy. The way George and Harold outsmart him with their pranks and comic-book twists makes him more of a comedic foil than a scary threat, which is why he’s so memorable. Honestly, I still giggle thinking about his 'name-change' charts—peak middle-school rebellion fuel.