Ke$ha used to have a tail, and she doesn't mean one of those animal-print things you clip to the back of your shirt, but an actual bone piece, sticking out of her back, which resembled a tail. She told her tale to Heat:
"I had a tail when I was born. It was a tiny tail, about a quarter of an inch, then they chopped it off and stole my tail. That was when I was little. I'm really sad about that story."
Guess she really is an animal.