Spirobranchus giganteus, commonly known as the Christmas tree worm, is a tube-building polychaete worm. The Christmas tree worm comes in many different colors.
As a juvenile it does live like a worm burried in the sand when it is ready it searches for a Coral mostly stony corals, drills a hole, builds and secretes a calcareous tube and develops the 2 spirals which divers are usually see if not retracted.
These are highly modified prostomial palps, which are specialized mouth appendages. Each spiral is composed of feather-like tentacles called radioles, which are heavily ciliated and cause any prey trapped in them to be transported to the worm’s mouth.