This insect is also called sea cucumber, and its scientific name is nudus, commonly known as "worm". Its shape is very similar to that of intestine, and it is a long cylinder with a body length of about 10-20cm. It is naked and hairless, and its longitudinal muscles are in bundles, and the annular muscles are staggered to form a square lattice pattern. Although starworm is not as valuable as sea cucumber, shark's fin and abalone, it tastes delicious and crisp, not as delicious as sea cucumber and shark's fin.

Growing in the coastal beach, because it is very sensitive to the growth environment, once it is polluted, it cannot survive, so it is called "environmental marker organism".