Captain Underpants and the Preposterous Plight of the Purple Potty People (Captain Underpants #8)
Have George and Harold completely lost their minds? Their time-travelling Purple Potty has landed them in a crazy place where the teachers are always nice, the cafeteria serves delicious food, and the school principal, Mr. Krupp, actually thinks they're funny. Something is very, very wrong - and it gets even wronger when the boys' pet pterodactyl, Crackers, and Sulu the Bionic Hamster are kidnapped by George and Harold's evil-twin look-alikes. Now George and Harold must face their cleverest enemies yet: THEMSELVES!