Clam worms are marine annelids that belong to the family Nereidae. Also known as sandworms, they are long, often brightly colored animals that burrow into the sand or mud of the seafloor. These worms are important prey for many marine animals, including birds, fish and larger invertebrates. To describe them, one could use words like bristle worm, ragworm, or polychaete worm. Other synonyms for clam worm might include tube worm or paddle worm, depending on the species in question. One thing is certain, though: whatever you call these fascinating creatures, they are a vital part of the marine ecosystem.