Tippy Tinkletrousers

"Hiya, class! I'm your cool new teacher! Not some scary guy with a secret evil agenda!"

- Professor Poopypants

Tippy Tinkletrousers, formerly known as Professor Pippy P. Poopypants (Pee Pee Diarrheastein Poopypants Esquire in the film) is a recurring antagonist in the Captain Underpants book series, and the main antagonist of DreamWorks's 35th full-length animated feature film, Captain Underpants: The First Epic Movie.

In the film adaptation, he was voiced by Nick Kroll, who also voiced Douche.

Book series
Poopypants first appeared in the fourth novel The Perilous Plot of Poopypants, where he was a brilliant inventor and scientist hailing from the country of New Swissland (where it is tradition for everyone to have a silly name, hence the professor's name), he travels to the United States with the goal of using a pair of inventions of his to reduce the world's garbage supply and increase the world's food supply. However, on account of his ridiculous name, no one takes him seriously.

Having had no luck with his inventions, Professor Poopypants takes a job at Jerome Horwitz Elementary School (ran by Mr. Krupp) as the new science teacher in hopes that the children would be kind and sweet-hearted. This proves false, however, as the students all laugh at his name, paying no attention in class. This goes on for weeks, driving the Professor to the brink of insanity.

He finally snaps when he reads a comic book written by George Beard and Harold Hutchins (the two main protagonists of the book series) further making fun of him. Using an enlarged version of his Gerbil Jogger 2000 invention, he holds the school hostage and shrinks them using his shrinking device, then makes them change their names to a silly name lest he shrink them down to nothing.

George and Harold (now Fluffy and Cheeseball) get Captain Underpants (now Buttercup Chickenfanny, but Captain Underpants didn't change his name and said he'd take orders from no one) to steal Professor Poopypants' enlarging machine, but unfortunately, he and the machine are shrunk in the process.

The two of them try to enlarge the school back to normal size, but get flicked off the school. Cheeseball makes a paper airplane that Fluffy enlarges. The plane flies into many threats, yet Captain Underpants rescues them and they end up in an abandoned alley. Fluffy tries to enlarge Captain Underpants (accidentally enlarging Cheeseball's right hand) to the size of Professor Poopypants' gerbil machine. Captain Underpants then fights and defeats Professor Poopypants. Once Professor Poopypants is defeated, everyone gets their names back. The boys use the shrinking and enlarging machines to get the school and Captain Underpants back to normal size. Then Captain Underpants gets soaked with water, turning back to Mr. Krupp.

Professor Poopypants is hauled off to jail. On the advice of George and Harold, he changes his name so no one will make fun of it anymore. Unfortunately for him, he chooses his maternal grandfather's name, Tippy Tinkletrousers, which his fellow inmates make fun of, much to his anger.

Tippy returns at the end of the eighth book Captain Underpants and the Preposterous Plight of the Purple-Potty People, where he is bent on revenge against George and Harold his mockery of his new name.

Tippy serves as the main antagonist of the ninth book (Captain Underpants and the Terrifying Return of Tippy Tinkletrousers) and the tenth book (Captain Underpants and the Revolting Revenge of the Radioactive Robo-Boxers), where he is bent on taking over the world using a time machine he created and a bomb to wipe out all life on the planet, though this only created a paradox that he couldn't escape. At the end of the tenth book, Tippy gets sent to the age of the dinosaurs with the bomb, which then explodes, killing Tippy and all the dinosaurs followed by two alternate versions of him both freezing to death after creating an Ice Age and getting molecularly destroyed alongside Crackers and Sulu, two allies of George and Harold, when he tried to destroy the Earth in vengeance.

Tippy is (arguably) the most evil villain of the series and Captain Underpants' arch-nemesis, judging by his actions of taking over the world and destroying life.

Film Version
In the film, Poopypants is the main antagonist, as he is bent on ridding the world of laughter because of the fact that people have made fun of his name for years.

He first appeared visiting Jerome Horwitz Elementary in hopes of being hired as the new science teacher. Captain Underpants (under his Mr. Krupp disguise) happily accepts and hires him because of his lack of common sense, as Poopypants is clearly insane (as well as unqualified for the job--as even Poopypants himself bluntly admits).

Despite trying to fit in with the school, Poopypants fins himself as a center of ridicule by the kids due to his silly name, Espically when George and Harold made a mockery comic about him.

Having enough of the mockery, Poopypants plots to take over the town, and recruits the local tattletale Melvin Sneedly to his cause after seeing that his brain has literary no sense of humour. Poopypants is also astounded to hear that Melvin has previously built a brilliant invention known as the Turbo Toilet 2000. With that in mind, Poopypants uses his technology to make the Turbo Toilet 2000 grow in size and uses wasted leftovers as fuel for the robot. He then uses Melvin's brain as a source to turn all of the school's students and staff into mindless zombies.

When Captain Underpants tries to stop Poopypants, the latter gets the Turbo Toilet 2000 to swallow Captain Underpants whole before capturing George and Harold, intending to turn them into mindless zombies to finalize his plan. George and Harold then apologizes to Poopypants for laughing at his name, and they admit he has the greatest name ever. But Poopypants still stubbornly states his name is not funny. George then tells Poopypants that his problem isn't that people laugh at him, it's that he can't laugh at himself. Still not convinced, Poopypants proceeds his plan. After he finally manages to corrupt George and Harold, he launches into a speech about his goals to conquer the entire universe. However, when he mentions Uranus, the very thing that sparked the boys' friendship, the duo regains their sense of humor, crashing the Turbo-Toilet's computer and freeing everyone from Poopypants' control. Following Melvin's defeat, Poopypants angrily attempts to shrink both George and Harold in revenge for foiling his plans, but Captain Underpants comes to the rescue, having escaped from the Turbo Toilet 2000's mouth by consuming the leftovers to gain superpowers. Captain Underpants then proceeds to defeat Poopypants and shrink him down. Defeated, Poopypants retreated by riding on a bee, only to be flicked away by Captain Underpants. It is unknown what happened to him afterwards though it is likely that he somehow returned to his original size but immediately was placed in prison for what he has done.

Trivia

 * Professor Poopypants is notable for being the first villain in the series who had a motivation to turn evil and take over the world; previous antagonists such as Dr. Diaper and the Turbo Toilet 2000 just came out of no where and wanted to commit world domination for no particular given reason.
 * Interestingly, in the film, Poopypants uses the Turbo Toilet 2000 as a weapon.
 * In the film, Poopypants is already a villain from the start, as opposed to being a well-meaning scientist who jumped off the slippery slope upon being mocked. His backstory reveals he'd already snapped when the presenters at the World's Greatest Inventor award ceremony were too busy laughing at his name to give him his well-deserved award. The school's mockery just further angers him, and he quickly takes the school hostage.
 * According to his resume in the film, he was born on April 1, 1953, he lives on 3.14 Smarty Pants Boulevard, and he lacks a phone. He also was in a very dark place, where his job was a revenge seeker.
 * Poopypants is arguably, because of his actions, the most darkest and most evil Captain Underpants villain in the whole series.
 * Poopypants is similar to Dr. Eggman: They are balding mad scientists who seek world domination, and rely on their inventions to help them succeed.