Piranha are greatly feared fish capable of turning an entire cow to a skeleton in a matter of moments. Though individually small, they swarm at the scent of blood, and are known to eat nearly anything, including humanoids. They are silvery or black, with pinkish underbellies (they tend to dwell in silty rivers where this matches the color of the water). Their bellies have sharp, saw-toothed scales, and their triangular teeth have a scissor-like sharpness.
When a new creature enters the piranha's area, there is a 75% chance that one takes a bite. If this happens, and a hit is scored, the rest of the shoal begins to swarm.
Outside of their native rivers, piranha are mostly found in the moats and traps of powerful dungeon-builders. Tribes native to the piranha's home employ piranha teeth as arrow or spear points, as or as edges for bone weaponry. Piranha are eaten by a variety of river creatures, including humans.