Finkenstein was a sixth grade student at Jerome Horwitz elementary when George Beard and Harold Hutchins where in kindergarten, he was Kipper Krupp's right hand man in his gang of bullies who bully the kindergarteners at Jerome Horowitz, he also attended wrestling classes along with the rest of Kippers gang.
Captain Underpants and the Terrifying Return of Tippy Twinkletrousers
Finkenstein and the rest of Kippers gang are first seen when they along with Billy Bill bullying Harold, but George notices them and after Kipper and his gang leave the scene he gets revenge on Billy Bill and he and Harold make friends and they go back to the school where Kipper and his gang are, George then takes out his tie and whips them causing the bullies to retreat to a nearby dumster. Then after that incident George and Harold decide to take down Kipper and his goons for good so they start pulling pranks on Kipper causing him to get embarrasedd in front of his friends and signing each prank as wedgie Magee, then one stormy night they left Kipper and his gang a comic book telling them the spooky tale of Wedgie Magee and convinced them that they where under a curse. Then after hearing a voice that was apparently Wedgie Magee (toy walky talky propped up against locker) they fled to the bathroom where they saw George dressed up in some stilts and a large pair of pants pulled over him, scared them to the extent that they ran home. Then from that day forward Kipper and his gang where nice to kindergarteners. But when Tippy Twinkletrousers goes back to the moment kipper and his gang fled the school he scared them to the extent that they went completely mad! So Kipper, Loogie, Finkenstein and bug all where sent to the goof house and Mr. Krupp was blamed for their madness and went to jail. Tippy then went forward in time to the present and due to mr. Krupp going to jail, there was no captain underpants and therefore the villains from books 1, 2, 3 and 5 had destroyed the earth completely.
Captain Underpants and the Revolting Revenge of the Radioactive Robo Boxers
due to the earth being destroyed, Tippy went back in time to the moment Kipper and his gang fled the school, he shrunk his old self and froze Kipper, Loogie, Finkenstein and bug before moving out of the way and unfreezing them and going forward in time now that everything was set right.