Horsehair worm

Found in freshwater environments such as ponds, streams, and puddles; larvae are parasitic within insects.

Larvae are internal parasites that absorb nutrients from the body fluids of hosts like crickets or beetles; adults do not eat.

As larvae, they manipulate the host's behavior to seek water; as adults, they emerge into water to mate, often twisting into knots (earning the name 'Gordian worm').

Harmless to humans, pets, and livestock. They serve an ecological benefit by controlling populations of insects like crickets and grasshoppers.