The Dweller in the Gulf, which appears only in the Clark Ashton Smith story of the same name, is an ancient, possibly immortal creature that dwells deep withing the planet Aihai (Mars). It is served and worshipped by a cult of Martians who have been captured and blinded by the Dweller, which is equipped with two proboscides for the extraction of eyes. The cult periodically gathers around a strange figure of the Dweller (the Eidolon of the Blind) which induces a drug-like ecstasy in anyone who touches it; while they are thus drugged, the Dweller claims one as a living sacrifice.
The Dweller itself has no eyes, but it does not appear to need them. Smith describes it thus: "The humped, enormous carapace, vaguely recalling the armor of the glyptodon, shone with a luster as of wet white gold. The eyeless head, alert but sonmolent, was thrust forward on a neck that arched obscenely. A dozen or more of short legs, with goblet-shapen feet, protruded slantwise beneath the overhanging shell...two proboscides, yard-long, with cupped ends, arose from the corners of the cruelly slitted mouth and waved slowly in air toward the earthmen.
The thing, it seemed, was old as that dying planet, an unknown form of primal life that had dwelt always in the caverned waters."