Anything with the name “vampire fish” should automatically be recognized as scary (even after Twilight), and payara are no exception. They are absolutely ferocious predators, capable of devouring fish up to half their own body size. Given that they can grow up to 1.2 meters (four feet) long, this is no mean feat. A large part of their diet is made up of piranhas, which should give you some idea of how tough these fanged fiends can be. They get their name from the two tusks that sprout from their lower jaw, which can grow up to 15 centimeters (six inches) long and which they use to literally impale their prey after viciously lunging at them. Their fangs are so big, in fact, that they have special holes in their upper jaw to avoid impaling themselves.