Nephasoma minutum is a marine invertebrate of the phylum Sipuncula, commonly known as peanut worms because of their shape when contracted.

These worms live in crevices in the rocks or in burrows in shallow water in Western Europe,[3] and the eastern United States.

[1] Reaching a maximum length of about 1.5 cm (0.6 in), Nephasoma minutum, like all peanut worms, has a cylindrical trunk and a narrower, retractable anterior section known as the introvert.

There are two tentacles and up to six irregular lobular projections near the mouth and there are a few irregularly-arranged, spine-like hooks near the tip of the introvert, but these may be absent in adults.

[5] Present from the lower intertidal zone down to about 50 m (160 ft), it burrows into sand, gravel and mud or hides in crevices in the rock.