Zombies

That'd be pretty scary.

well zombie birds are the worst, grrrrrr I hate them so much

Shuffler. Easy to get away from, especially if it had suddenly come upon water and sank to the bottom. It would be a while before it made it's way to the top, if it could. Since they are dead, they don't breath. They could be trapped under water, and still be there when you are miles away.