Identifying a Thin White Worm in a Lily Pond: Horsehair Worm or Something Else?

Not a Snake

Snakes are much thicker. A 12-inch, spaghetti-thin, white worm is almost certainly a horsehair worm (Nematomorpha).

Bizarre Life Cycle

1. Adults lay eggs in water.
2. Larvae are eaten by crickets/grasshoppers.
3. Worm grows inside insect, manipulating its behavior.
4. Infected insect seeks water and drowns.
5. Adult worm emerges, repeats cycle.

Harmless

They parasitize only invertebrates. No threat to fish, plants, or humans. A sign of a healthy insect population.