Here are a few that aren't twisted in the horror or SiFi genre but in a dark comedy.

Tim Dorsey who has a character Serge A. Storms who appears in all his book. Never the main character but all way in the thick of things. Serge has a variety of mental illnesses with the right mix of drugs can be controlled which he rarely takes. When he's not finding some of the most twisted and funny ways to kill people who have offened his sences of right and wrong. He's running around Florida giving impromptu tours and history lesons.

Bill Fitzhugh's Pest control main character is anexterminator that get mistaken for a hit man (because of the way he worded a flyer). Even thoe he keeps telling everyone who tries to hire him he just an exterminator. The people they want him to kill die in mysterious ways that he ends up getting the cridet for. Soon he has five of the worlds top hit men gunning for him. finding a way to get out alive.
Bill aslo has other twisted books
Cross Dressing when the main character's tiwn brother the priest come home from africa sick he send him to the hospital under his insurance whne his brother end up diring he takes over his brothers life to keep from being charged with insurance fraud.
Heart Seizure when the main character's mother is finely going to get the heart trasplant she needs the heart is snatched away by goverment agents which he in turn snatches back leading to a wild chase to get the heart where it is needed.

Cristopher Moore who has one of the truely most tisted sense humor that I've ever read

__________________
it's only kinky the first time

it's not the orgasm but getting there thats fun

a shot in the bush is worth two in the hand

whip me, beat me, tie me up, break my arm, but please don't break my heart

"The trouble with the world is that the stupid people are cocksure and the intelligent are full of doubt" -Bertrand Russell