The Spawn of Nyogtha are a fictional race created in 1995 by Chaosium for the Call of Cthulhu RPG.
The Spawn of Nyogtha are produced by the blasphemous unions between ghouls, humans, and Nyogtha. Which within 3-6 decades degenerate into shapeless abominations. During the first decades they easily pass for a human. Running through their bodies is not blood but a viscous black ichor. They are charismatic, strong, and tough creatures whom serve Nyogtha and seduce others into its cult.
Once degeneration begins, within a few months they complete their metamorphosis. Which starts with hideous black splotches appearing on the flesh which quickly spread, while the spawn becomes ravenous. It's final form is one of squirming and writhing slimy flesh, skeletal hands with razor-sharp talons, hideously distorted features on a skeletal face with lupine fangs and bulging eyes, and bloated corpulent torso and limbs.