The Ghost Cat lives in the large bell that he wears around his neck. He is constantly searching for a fiancee, and has a smaller version of his bell. Whomever holds this bell becomes his fiancee.
Originally Shampoo holds the smaller bell, but refuses to have anything to do with the Ghost Cat. After finding out that Ranma is her fiance, he decides to haunt Ranma.
Of course with Ranma's intense fear of cats this only makes him revert to using his Cat-fu on the Ghost Cat. Finally he sees that he is no match for Ranma and decides to look for a fiancee elsewhere.
Maomolin returns once again to claim Shampoo as his bride on New Year's Eve 1991. He takes her to the Cat Temple and seals her in. Once she leaves she immediately changes into her cat form. Only a kiss from Ranma can break the spell, which will be permanent once the 108 New Year's bells toll.