Katrina Madd, commonly known as Katrina the Keeper of Cats on Cat Cay Island, is the main antagonist of the 28th Give Yourself Goosebumps book, Night of a Thousand Claws.
She lives on Cat Cay Island, and she is described as a woman who is able to transform into a cat girl at will. However, if the reader achieves a good ending, the reader can make her human again.