Very few predators think humans would make a tasty treat, but polar bears are members of that exclusive club. While shooting his BBC documentary series The Polar Bear Family and Me, filmmaker Gordon Buchanan was approached by a hungry, 1,000-pound polar bear as he sat in his plexiglass pod. He marvels at her…

Yes, it sounds like the name of an awful horror knockoff (this one, to be exact), but a 22-pound beast known as Megapiranha paranensis once roamed the water 10 million years ago, and its bite was truly something to fear.

The recently discovered harp sponge, Chondrocladia lyra, make not look like something you'd bring into the bathtub, but what it lacks in sponginess it more than makes up for in predatory behavior. The harp sponge uses those narrow spines to snare small fish and crustaceans, which it then digests whole.

The theropod dinosaurs, like Tyrannosaurus rex and Velociraptor, were some of the most fearsome carnivores ever. Yet most of these perfect hunters abandoned live prey in favor of a more peaceful, vegetarian existence...which started their evolution into birds.