Living amongst the Gillikin people, Mombi was feared and hated by the majority of the people around her. Although the Good Witch who ruled that area of Oz had made it illegal for anyone else to be a witch, Mombi was classed as a sorceress or wizardess at most.
She raised the young orphan Gillikin boy Tip. However, she over worked him and snapped orders at him, which made him dislike her. Therefore, when Mombi made a two-day journey to the market, Tip created Jack Pumpkinhead to scare her.