These sharks grew to be about 15 feet long

These sharks grew to be about 15 feet long, and had a lower jaw that was made of a “tooth whorl”. It looks like a cross between a circular saw and a shark, and when you mix apex predators with power tools, the world quakes in fear.

Helicoprion’s teeth were serrated, implying that they were definitely carnivores, but there is some debate as to whether their teeth were in the front of the mouth, as shown in the picture, or if they were farther back, which would suggest a softer diet, like jellyfish. However it was arranged, it clearly worked; Helicoprion survived the Permian Triassic extinction, which means they may have been smart enough to create bomb shelters. Or maybe they just lived in the deep sea.