Lepas anatifera - Gooseneck 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.