Researchers have discovered the remains of an ancient shark that had super-sharp teeth and horns on its head.  Let the nightmares begin...

The newly discovered species, dubbed Diablodontus michaeledmundi (or "Devil Tooth"), lived 260 million years ago; so don't worry about running into one on your next trip to the ocean.

The shark was likely 3.5 feet long, had spikes on its fins, and probably ate soft animals including small fish, experts say.

[via Newser.]

So...yeah.  Terrifying.  I'm sure glad we missed Devil Tooth by a couple hundred million years!