Lepas sp.
goose barnacle

Family Lepadidae

Barnacles are Crustaceans, related to crabs and prawns. Goose barnacles have long rubbery stalks, with which to attach themselves, usually to floating objects. Legend has it that the name goose barnacle comes medieval Europe. The cirri resemble birds' feathers. The geese flew south each winter and they appeared not to lay eggs on land so it was conjectured that barnacles on their floating 'islands' were goose eggs.

Distribution =   worldwide, attached to floating objects
Max size =   4cm