A lugworm is a marine annelid worm belonging to the family Arenicolidae. It has an elongated, cylindrical body and segmented appearance. Lugworms are commonly found in sandy coastal areas, where they burrow into the substrate. They play a crucial role in enhancing sediment turnover and nutrient cycling. Their burrows also provide a habitat for various organisms. Lugworms are known for their ability to survive in oxygen-poor environments and are often used as bait in recreational fishing.