It grows to a diameter of about 15 cm (5.9 in) and has an inflated appearance as the entire aboral (upper) surface is covered by a thick, raised, fleshy membrane.

This has a smooth soft texture and is pale brown, grey, red, or orange, often with a symmetrical darker pattern.

[4] The slime star occurs in rocky areas on the west coast of North America from the Bering Sea southwards to central California at depths to 950 m (3,120 ft).

[4] The slime star feeds on various benthic invertebrates, including the breadcrumb sponge (Halichondria panicea), the false jingle shell (Pododesmus macroschisma), other scallops and clams, and colonial sea squirts such as Aplidium and Didemnum species.

[3][4] One of several different species of polychaete worms often lives symbiotically within the ambulacral grooves on the oral (under) surface of the slime star.