Professor Poopypants

Professor Pippy Pee-Pee Diarrheastein Poopypants Esquire (later Tippy Tinkletrousers) is one of the antagonists on the Captain Underpants book series. He debuted in the fourth book Captain Underpants and the Perilous Plot of Professor Poopypants, in 2000. He later appears in The Preposterous Plight of the Purple Potty People, The Terrifying Re-Turn of Tippy Tinkletrousers, The Revolting Revenge of the Radioactive Robo-Boxers, and The Tyrannical Retaliation of the Turbo Toilet 2000. He also appears in Captain Underpants: The First Epic Movie as the main antagonist.

Further information
Professor Poopypants on the Captain Underpants Wiki