Piranha

Terrible Teeth: Piranhas are known for their sharp, pointed teeth and sharklike feeding frenzies, but the threat to humans is largely exaggerated. Although the piranha is usually small (the red piranha grows no longer than 13 inches), their teeth are set in powerful jaws, and top and bottom teeth interlock, giving the freshwater fish its ability to tear and rip flesh.

Insects to Horses: Victims are usually animals smaller than themselves such as insects, aquatic invertebrates and other fish, although attacks on animals as large as horses have been witnessed. Some human deaths have also occurred.