"In case you had forgotten," replies the mouse "I turned you into the cat you are now. If you attempt to eat me, you will be permenently allergic to yourself and spend your whole life sneezing!"
"Good point." you reply. This little mouse is your master now, strange as it may seem. "How many rats are there here anyway?"
"About 40. Some of them know black magic too. They killed off the human family, and my family too, but I managed to steal some of their magic."
"I'm sorry." you say "I'll help you get rid of the mice."
"Thankyou." replies the mouse "I promise I'll give you your human body back, and you can choose whether or whenever to be a cat."
"Come to think of it, I'm starting to like cats." you say "Do you have a name?"
"Philly"