Mr. Toggle is a roboticist who created a robotic piano teacher known as Dr. Shreek and works at his building posing as the maintenance man. When Dr. Shreek starts attacking Jerry for his hands, Mr. Toggle shuts him down
Mr. Toggle then reveals that he is obsessed with collecting his students' hands because he can't make human-shaped hands correctly. In the end, he is taken away by a bunch of ghosts from the disembodied hands and dragged into the forest behind the school never to be seen again.
- In the televised adaption of the book, Mr. Andrew Toggle (portrayed by Géza Kovács) is shown to have a history with the piano teacher ghost who called him a "lazy boy" when he didn't do his piano work. When Mr. Toggle tries to claim Jerry's hands, the piano teacher ghost arrives stating that Andrew had gone too far this time. Andrew starts pouting stating that he tried his best even when she pressured him to practice back when she was alive. She then evokes her wrath upon calling on the other ghosts as Jerry runs out of the school. In the final scene, the piano teacher ghost says, "This is your punishment for terrorizing the boy! You will practice and practice!" Mr. Toggle asks in a sobbed "How much longer?!" The piano teacher ghost replies, "Till....eternity, you lazy boy!"