|Beyond a gulf in the subterranean night a passage leads to a wall of massive bricks, and beyond the wall rises Y'golonac to be served by the tattered eyeless figures of the dark. Long has he slept beyond the wall, and those which crawl over the bricks scuttle across his body never knowing it to be Y'golonac; but when his name is spoken or read he comes forth to be worshipped or to feed and take on the shape and soul of those he feeds upon. For those who read of evil and search for its form within their minds call forth evil, and so may Y'golonac return to walk among men . . .|
Y'golonac is a Great Old One and is the god of perversion and depravity – not just "average" human perversions or depravities, but any that can be conceived of by a sapient being (sane or otherwise). His demeanor is much like that of Nyarlathotep, but he is much more perverse and sadistic. Y'golonac can sometimes be summoned merely by reading his name (not necessarily aloud; just reading it is sufficient) in the Revelations of Glaaki.
Y'golonac is imprisoned behind a wall of bricks in unknown ruins. His true form is uncertain, but when he possesses a human host to manifest, he appears as a grotesquely obese man, lacking a head or neck, with a mouth in the palm of each hand.
Unlike Lovecraft's deities, Y'golonac is clearly capable of understanding humans, to the point of being able to conduct a conversation in English through his human host. Y'golonac seeks humans who read perverse and forbidden literature to become his servants. When Y'golonac is summoned, he offers to grant the summoner the dubious honor of becoming his priest, or simply kills him for food.
- Campbell, "Cold Print", p. 204.