Shampoo, after returning from her visit to China, gives Ranma a giant cat bell as a wedding present. however, the bell is cursed with the spirit of a giant ghost cat, who searches for the wearer of the matching smaller bell, to claim as his bride.
Shampoo was in possession if it, but told the cat she was in love with Ranma, and had to defeat him in order to be her bride. as a result, it kept on chasing after Ranma, who was terrified of cats.
however, it wasn't defeated until Ranma rejected Shampoo, who responded by shoving him in the water with the small bell, turning him into a girl, and the object of the cat's intention. however, as the cat was hugging her, girl-ranma entered cat-fu state, and soundly beat the cat, chasing it away.