She appears as a gigantic brittle star, with a massive disk, radial symmetry, and short arms that lack tube feet. The upper portion of her disk appears as a giant mound of turquoise colored, crystal-like "material" with multiple geometric facets. The lower-half of the disk is colored a darker shade of turquoise. The arms are joined near the middle of the disk and taper to a point outwards; they are also turqoise in color, albeit in an even darker shade than the disc's underside. The ventral side of the disk contains a drill-like apparatus that can unfurl to reveal five turquoise colored arms, which appear to have fingers, that surround a mouth. The dorsal side of the disk houses multiple Drill Parasites that furl themselves to form spike-like protuberance that the Gem Cave Creature can launch.
The Crystal Gems confront the Gem Cave Creature in her lair; after a brief clash, Garnet successfully defeats her and bubbles away her gemstone.
Burrowing: The Gem Cave Creature has the ability to burrow underground by using the drill underneath her disk.
Body Manipulation: She can unfurl her drill to produce five more arms to enhance her fighting capabilities. Her arms also have the ability to stretch to great lengths, as seen when she was battling Garnet.
Creature Creation: She can launch multiple spikes from her disk, which can unfurl and become Drill Parasites that can aid her in battle.
Gem Cave Creature resembles Brittle Stars more than a Starfish.
Brittle Stars (Ophiuroids) resemble true Starfishes/Sea Stars (Asteroids), but the main difference is that brittle stars have a distinct central disc and five radiating slender, highly flexible arms. The arms are solid and not hollow like the sea stars, whose central disk and arms are inconspicuously parted.
She is featured as an enemy that Steven must avoid in Gem Bound, as well as a second yellow variety.
The Gem Cave Creature's gemstone is light blue and possesses multiple facets on all sides with cone-shaped spikes protruding out of each vertex. It is a icosahedron. It is located somewhere within her head.