Friend of mine recently introduced me to the Cthulhu mythos, and he's been pestering me for awhile to buy Alhazred, Author of the Necronomicon. It's not written by Lovecraft, but it's set in his Cthulhu mythos.

God...damn...

As far as sheer gross, it's hard to beat. On page 20 the main character is forced to eat the miscarriage of his lover, the king's daughter. It was a 4 month fetus, and it is grilled and then shoved down his throat. Then the same is done with the man's nose, ears, dick, and balls.

The creepy part is, it's all written from a first person perspective, but the wording is all...clinical. This is partly due to the fact that it's first person but past tense, but still...there's no horrified recount of the events, merely enough to let you know how the man felt about things as they happened. Not enough to inspire those same feelings in you. Alhazred speaks as if talking about what he had for dinner. (Which is frequently rats or dead people.)

Great book. I recommend it to all who are strong of stomach.