Dr. Pipt is a character who showed up in The Patchwork Girl of Oz and is the creator of the titular heroine. He is also known as the Crooked Magician because his body is rather crooked and he practices magic in defiance of the laws of Oz.
As I was reading the story as research for AiO, it felt a little jarring to have Dr. Pipt's magic stripped from him at the end of the story. He's not a villainous character, nor is he unsympathetic, and yet Ozma treats him much like a criminal in the climax of the story. So what did he do that was so terrible?
1) Improper storage of magical liquids. This is what creates the main thrust of the story, as the Liquid of Petrifaction is spilled on Unc Nunkie and Margolotte which requires Ojo to undertake his journey in the first place. But it's not his only crime. Read on.
2) Improper use of magic to solve a mundane problem. Bungle the Glass Cat was originally created to catch mice around the Pipt home. To drive home this particular lesson, it backfired on him. Bungle has no stomach with which to digest mice and her other features are notable enough that she's rather pay attention to those. (Baum repeats this theme in a conversation between Dorothy and Ozma in Glinda of Oz)
3) Animation with intent to enslave. Probably a strong term there, but it's accurate. Scraps was intended to be a servant. Her original batch of magical brains was intended to make her competent and complacent in her role as maid. It was Ojo's additions that made her a unique and independent character.
4) Animation and abandonment. This is poor Vic, the living phonograph. He was brought to life when Scraps knocked the Powder of Life from Dr. Pipt's hand. He likes to do what he has been built for, which is to play the record on his turntable, but it's a horrible record and so he is cast out by Dr. Pipt.