A reader recently submitted a question via the All About Worms Facebook page about a worm “coming out of the ground” in his garden. The most distinguishing characteristic of the worm is that it is “very thin, almost like nylon fish line,” and it moves in a “swaying motion.” The reader only asked if what he found is a type of worm, but we’ll do him one better by identifying the exact worm we think he found: a horsehair worm (occasionally spelled “horse hair worm”). Since horsehair worms are nematodes (roundworms), they are actually worms, not just creatures that everyday language, with its understandable but often frustrating contempt for scientific precision, has wrangled into the “worm category.”

A reader asked us to identify the super-thin brown worm he found in his yard. We are confident this creature is a horsehair worm!