A cat organ is a musical instrument in which a series of cats are arranged in a row by vocal range, with their tails secured inside the machine with a keyboard attached, such that when a key is played the corresponding tail is pulled and makes the cat yell.
Discussed by Robert J. Richards in a psychiatry context.
Referenced in this music ensemble posted recently on BBC news, where Prince Charles just thinks this is the funniest damn thing ever, even though they're only playing "Somewhere Over the Rainbow" using toy doll cats (animal rights people, you can relax now).
Meanwhile the Wiki page on cat organs describes some pretty disturbing abuses of animals for entertainment's sake in general.
Would you believe there's a whole field called "zoomusicology", dedicated to the use of fauna in composition? There is an elephant orchestra in Thailand, thankfully with the elephants playing instruments rather than being the instruments themselves. And then there's Hatebeak, a death metal band employing a screeching parrot for vocals (and they still sound better than Nickelback).