Naval Shipworm

Naval shipworm, Teredo navalis, is a saltwater clam of the family Teredinidae, commonly called a shipworm for its worm-like elongated body despite being a true bivalve mollusk, bearing a small two-valved shell only at its anterior end. It is the type species of the genus Teredo and is well known for boring destructively through submerged wood, historically causing extensive damage to wooden ships and harbor pilings, which gave the species its common name.