These enchanting spirals are actually the tongue and gills of a Serpulid Tube Worm. These tiny creatures embed themselves into the coral, exposing only this feathery extremity. Not only do these spirals provide both food and oxygen, but they are also photosensitive and pressure sensitive. A shadow cast upon the creature or a gentle swish of water nearby will make the serpulid worm instantly retract the spirals.

I photographed this specimen in the Solomon Islands.