Lepas anatifera

Species of barnacle

Lepas anatifera, commonly known as the pelagic gooseneck barnacle or smooth gooseneck barnacle, is a species of barnacle in the family Lepadidae. These barnacles are found, often in large numbers, attached by their flexible stalks to floating timber, the hulls of ships, piers, pilings, seaweed, and various sorts of flotsam.

From Wikipedia, under CC BY-SA. More on occurri.