This delicate filament is the feeding apparatus of a sea worm. In this case the worm is embedded in the sand. When bothered, the filaments withdraw, so I must be careful not to disturb the water too much when capturing this kind of sensitive animal. See related worm filaments images, Right Angle Christmas Tree Filaments and Feather Duster.
This image is printed in the square format up to 8 x 8 inches