The Purple Potty Time Traveler takes George and Harold into a crazy situation in the eighth book of this New York Times best-selling series, written by Dav Pilkey, author and illustrator of Dog Man. The teachers are friendly, the cafeteria serves delicious food, and the school principal, Mr. Krupp, thinks George and Harold are hilarious. Something is very, very wrong, and it gets even worse when Crackers, the boys' pet pterodactyl, and Sulu, the bionic hamster, are captured by George and Harold's evil twins. Now George and Harold must face their greatest enemies yet: THEMSELVES! Can they handle this mess on their own, or will they need Captain Underpants to step in and save the day?