Horsehair worm

Freshwater environments such as ponds, streams, troughs, and puddles; also found inside terrestrial insect hosts.

Larvae are internal parasites of insects (crickets, grasshoppers, beetles); adults do not eat and function only for reproduction.

Adults are free-living and form knotted masses (Gordian knots) during mating. They manipulate their host's behavior to seek water, where the adult worm emerges.

Harmless to humans, pets, and plants. They are beneficial for the ecosystem as they help control populations of insects like crickets and grasshoppers.