Calcareous tubeworm

''Serpula vermicularis'', known by common names including the calcareous tubeworm, fan worm, plume worm or red tube worm, is a species of segmented marine polychaete worm in the family Serpulidae. It is the type species of the genus ''Serpula'' and was first described by Linnaeus in 1767. It lives in a tube into which it can retract.