A while ago I had a nightmare where I found myself trapped in "hell". I don't know how or why I ended up there, but the creatures around me didn't seem aware of my presence. I knew that they could "sense" I didn't belong, but as long as I hid in the shadows and stayed still, they couldn't find me. So my brain decided to conjure up all kinds of twisted imagery for me, one of them was a gluttony demon.
It was a massive maggot with human skin; its body filled most of the cave where I was hiding. The creature's abdomen was lined with open sores and hands, slowly crawling forward. Mouths had broken through the flesh on it's lower body to lick up and eat all the filth around the floor and walls of the tunnel.
There was a sense that dragging its body around caused incredible pain, but it was unable to stop. As it neared, I realized the creature had once been human. Its eyes bulged almost out of the sockets, and the jaws and teeth had grown past what should fit inside a human face, tearing the skin along its cheeks. It kept moving forward, always looking down, teeth scraping the ground, forced to feed on the rotting flesh and filth littering the floor.
The image haunted me for days, and it was so vivid that I had to try and recreate it.