C'hulagen

C'hulagen is one of the old dark gods of the Necrotelicomnicon, an inhabitant of the Dungeon Dimensions that has somehow made it into the Discworld reality.

It is mentioned, along with Bel-Shamharoth and the Insider, in Equal Rites.

Annotations

The name C'hulagen is a riff on Lovecraft's Cthulhu, and possibly a pun ('cool again', as the Cthulhu mythos had become when Equal Rites was written).