I suspect Gygax made it up, but it's most certainly Cthulhu inspired.Who thought of the Mind Flayer? It doesn't seem mythological to me, and this question has been burning me for a while.
Geoffrey said:Actually, the very first appearance of the mind flayer was in The Strategic Review #1 (the precursor to Dragon magazine), way back in 1975. It doesn't have a by-line, but most of the stuff in those early days that didn't list its author was by Gary Gygax.
mmadsen said:Now I want to know where the heck the Gnoll came from. Hyena men? Is there some famous fantasy classic with hyena men?