Cthulhu Mythos

"Well make a horror movie with a happy ending" -
They don't have happy endings, it's a horror movie. It's supposed to end horrible. -Ice T
HP Lovecraft wrote some horrible things, like "poems" that make you forget all about Horror at Redhook. But maybe having a mind full of horror-ble stuff makes you write horror that establishes genres.
Call of Cthulhu, Trail of Cthulhu, miscellaneous cosmic horror. These games will all end horrible.