Giant sea stars have small eggs, and their sperm contain spherical heads.

By the time they mature and reach adulthood they are centered on a set point with radial symmetry to their bodies.

They contain thick, blunt spines that are bluish in color with white, pink or purple tips that are swollen and surrounded by brown fuzz and pedicellariae that have a plier like shape.

They prey on several kinds of sea organisms including barnacles, gastropods, bivalves, and limpets.

It eats its prey by extending its stomach so it can fit into tiny gaps, such as mussel shells.