Full title: Operation Acoustic Kitty: The CIA spent about $15 million surgically implanting a microphone in a cat's ear, a transmitter under its skin, and an antenna through its tail to spy on Soviet conversations
well, that's just for spying. I still think ww2 was worse, when they would feed dogs under tanks, so that when deployed in the battlefield, the dogs with explosives strapped would get under enemy tanks and boom