What links together two bands of worshippers, one deep in the Arctic snows, one hidden in the bayous of Louisiana, is more than their shared practice of blood sacrifice. It is the inhuman phrase they both chant: Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn—“In his house at R'lyeh dead Cthulhu waits dreaming.” Now these nightmares will disturb...