Finkenstein was a sixth grade student at Jerome Horwitz Elementary School when George Beard and Harold Hutchins were 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 Kipper's gang.
Captain Underpants and the Terrifying Return of Tippy Twinkletrousers
Finkenstein and the rest of Kipper's gang are first seen 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 dumpster. Then after that incident, George and Harold decide to take down Kipper and his goons for good, so they start pulling pranks attributed to "Wedgie Magee" on Kipper, causing him to get embarrassed in front of his friends. One stormy night, they leave 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 (a toy walkie-talkie propped up against a locker), they fled to the bathroom where they saw George dressed up in some stilts and a large pair of pants pulled over him. This 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 Tinkletrousers 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 Bugg were sent to the Piqua Valley Home for The Reality Challenged, and Mr. Krupp was blamed for their madness and was fired as a result. Tippy then went forward in time to the present and found that Dr. Diaper, the Talking Toilets, and Zombie Nerds had destroyed the Earth because Captain Underpants was not there to stop them.
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 Bugg before moving out of the way and unfreezing them and going forward in time now that everything was set right.