Echiurans, also known as spoon worms, are a group of marine invertebrates belonging to the phylum Annelida. They are characterized by their elongated, soft bodies and a distinctive spoon-shaped proboscis used for feeding. Echiurans typically inhabit sandy or muddy substrates in shallow coastal waters, where they burrow into the sediment. These creatures can vary in size, with some species reaching lengths of up to 50 centimeters. Echiurans are mostly detritivores, feeding on organic matter in the sediment. They play an important role in the marine ecosystem by contributing to nutrient cycling and serving as prey for various marine animals.