It's the invented script from the Cthulhu mythos by the gothic horror writer HP Lovecraft. Cthulhu slept at the bottom of the sea, before being awakened by man

It's the invented script from the Cthulhu mythos by the gothic horror writer HP Lovecraft. Cthulhu slept at the bottom of the sea, before being awakened by man or something. I don't know, I haven't read it. That's what the big scary monster thing to the left of the script is. It's a big part of geek culture, it made its way into D&D, and via that into everything else.