The tone of AUs.
AUs that, as opposed to Comedic AUs, actually hold a serious story and such.
AUs that are mostly comedic in nature. Bare in mind that a Parody can be bother dark or comedic so they aren't necessarily the same thing.
A category for the 'Fell' version of other AUs (e.g. Swapfell if a fell iteration of Underswap.)
Warning: Some of these AUs contain themes that may be disturbing to some viewers.
AUs with the goal of creating something scary, insane, or disturbing. Some AUs that follow the genocide route are also found here, but not all are geno-route-only. Some possible themes include suicide, drug use, alcohol use, depression, death, gore, insanity, disfigurement, pain, etc. Horror can also include Terror, and effects on psychology. This could include things like dystopias and the like.
It is suggested you read the short bios of these before googling them!