Starfish

Though called 'starfish', these organisms are more closely related to jellies than to any other animal. They may have evolved from stalked jellies. They are characterized by radial symmetry and in some cases by hard mineralized shells.

—Shootroots: some starfish have evolved a niche as bottom-dwelling mineral-seekers, burrowing into the seabed with hard plastic fibers perhaps evolved from jelly tentacles.

Earth analog: biologically none; visually akin to starfish, sea lilies or the extinct blastoids.