The Sleeping City — E.C. Tubb

From the opening reared a head, wide, flat, huge. Below it stretched a body beautiful with iridescent scales of gold edged with ruby. Nictitating membranes lifted over enormous eyes, deep, limpid pools of ancient wisdom, catching and reflecting the light of the miniature sun, turning the glowing orb into a scatter of stars shimmering in an ebon sea. From open jaws a forked tongue flickered with a soft susurration. Its scent was dry, acrid, tinged with that of living fur on a summer's day. The head rose higher, swaying over the three men on the ledge, the sinuous length of the body almost filling the passage through which it had come. From it radiated an impression of incredible age.

"A serpent, " whispered Thagamista. "A creature from the beginning of time. Somehow surviving to find this place and feast on those who dwell here. It was inevitable they should think it a god."