Yesterday I bought Green Devil Face 1, 2, & 3 and Death Frost Doom because I'd heard such good things about them. I haven't yet had the chance to peruse them, but I'm really looking forward to doing so.
But I do have a question. It seems that the Green Devil Face, aside from meaning an obvious trap, actually comes from something, and while it seems familiar (ToH maybe?) I can't find anything that says "from this source". So I want to know, does the Green Devil Face actually come from a specific module? If so, which one, and where?