The hippopotamus amphibius, or "river horse," is responsible for several hundred human fatalities each year—more than lions and crocodiles put together. Its tusks, which often appear adorably Chiclet-like in artistic depictions, are actually long and sharp enough to cut a full grown man in half. A hippo can run up to 30 miles per hour, so if one charges you and you're not carrying artillery-grade weaponry, you're pretty much fucked. However, if King Hippo charges you, all you have to do is throw a punch at his open mouth and then hit him in the stomach about 50 times while he's trying to pull up his pants. RATING: 91%
(Image from z.about.com.)