Colossal Squid.

This massive creature was found in Antarctic waters, and it is only two-thirds its estimated adult length. Its scientific name is Mesonychoteuthis hamiltoni, but the scientists who have been examining it are calling it "colossal squid":

"We feel that colossal conveys both the size and the aggressiveness of the animal.

"This animal, armed as it is with the hooks and the beak that it has, not only is colossal in size but is going to be a phenomenal predator and something you are not going to want to meet in the water." — BBC

The species has been known to "maul sperm whales."