Professor Pippy P. (Pee-Pee) Poopypants is a brilliant scientist who wants to change the world for good – but his ridiculous name means no-one takes his fantastic inventions seriously. And when the kids at Jerome Horwitz Elementary laugh at his name too, poor Professor Poopypants SNAPS! Now crazy Professor Poopypants is on the rampage! He is armed with fiendish inventions Shrinky-Pig 2000 and the terrible Gerbil Jogger 2000 – and he’s ready to use them! Only Captain Underpants can stop Professor Poopypants from shrinking the world to the size of a pair of pre-shrunk pants – and save its people from a fate even worse than shrinkage: being given a terrible toilety name like Fluffy Toiletnose, Poopsie Chucklebutt and Chim-Chim Diaperbrains.