Large sedentary bristle-worm (polychaete) that inhabits U-shaped tubes in sand or mud. The tube can be 23 cm/9 in long and the two ends protrude from the surface and can be seen at a very low spring tide.

The worm's body, which is phosphorescent, is divided into three regions with various sizes of fans and bristles. These aid in spinning a mucous net, which filters out particles suspended in the sea water and is then eaten by the worm, another being spun in its place about once an hour.

Classification
Chaetopterus is a member of class Polychaeta in phylum Annelida.