All of the mice met in council to discuss the best way to secure against attacks of the cat. After several suggestions were debated, a mouse of experience and standing got up and said: "I think I have hit upon a plan which will ensure our future safety." We will fasten a bell around the neck of our enemy, the cat, which by its tinkling will warn us of her approach." As the proposal was being applauded, a mouse who was even wiser stood up on his feet and said: "It is easy to propose impossible solutions. I agree that it is an admirable plan, but who is going to bell the cat?"
(aesop fable)
"If your cat falls out of a tree, go indoors to laugh."
-- Patricia Hitchcock
In a multiple cat household with a member who is terrorizing the other cats, consider putting a bell on the aggressor. This eliminates the element of surprise that an overly playful cat may use to startle the other cats. It allows the other cats and the owner to know where the rambunctious feline is at all times.