Horsehair worm

Stagnant or slow-moving water, puddles, and domestic water fixtures like sinks or toilets

Non-feeding as adults; larvae are internal parasites of insects like crickets and grasshoppers

Adults are free-living in water to mate; larvae control host behavior to force them toward water for the worm's emergence

Harmless to humans, pets, and plants; beneficial for natural pest control of arthropods