This incredible little animal is called Dosima fascicularis, otherwise known as a buoy barnacle. The brilliant blue coloring is typical of the species, and a very special species it is. Special, and decidedly phallic shaped too!
Barnacles are related to crabs and lobsters but live attached to a hard substance. Some are able to grow their shell permanently onto something like the hull of a boat or other structures, while another order called “gooseneck” barnacles attach themselves with a stalk. The buoy barnacle is unique in that it is the only one that can make its own float or attachment.
It floats head downwards, and even though it can attach itself to timber or other floating debris, it can also create its own float which looks like a polystyrene foam. Some buoy barnacles get together and all attach to one big lot of foam, while others make themselves individual floats as seen in the first picture. The star shaped appendage is actually the barnacle’s foot, which it uses by beating it in its water column to attract food.