Captain Underpants #4

Professor Pippy P. (Pee-Pee) Poopypants is a brilliant scientist, but his ridiculous name means no one takes his fantastic inventions seriously. And now he's on the rampage! He's armed with fiendish inventions Shrinky-Pig 2000 and the terrible Gerbil Jogger 2000. Can Captain Underpants stop him?