Mr. Toggle

Mr. Toggle is the main antagonist in the Goosebumps book ''Piano Lessons Can Be Murder. ''He is an inventor who works at a piano school, but steals the hands of students to play music without human error interfering. He is also the creator of Jerry's piano teacher, Dr. Shreek, who is actually a very lifelike robot. At the end of the book, the ghosts of his former students chase him from the school. In the TV episode, the ghost haunting Jerry's house forces him to practice the piano for eternity.