The last two-headed animal find I read about was a snake and I would say that's more common than people think. Now a two-headed deer? I'd say that's extremely rare. One was sort of harvested in Western Kentucky.

Hunter Bob Long saw a deer with big antlers, he took aim, and he discovered the deer had a friend, er, another head. Look:

It looks like sorcery but for now, this is one for the storytellers. That's something you don't see every day or deer season.