I'm happy to admit that I have a lifelong love for strange movies. I would rather watch something that can better be described as "disturbing" rather than "gory" and there's something much more entertaining about an incoherent train wreck of a film than one that tries to be traditionally funny. The following movies really ought to be watched in one, long marathon for anyone interested in pushing the limits of what a single person can take over the course of a day.
Naked Lunch (David Cronenberg, 1991)
I'm going to begin and end the Messed-Up Movie Marathon with the man I consider the undisputed king of mind-bending cinema, the singular David Cronenberg. Just a few years before the death of controversial author William S. Burroughs, Cronenberg decided to attempt an adaptation of his most famous work, a nigh-unadaptable novel called Naked Lunch. The resulting film is more of a companion piece to the book than a direct translation, but that doesn't mean it's any easier to follow. The film stars Peter Weller as a stand-in for Burroughs, stumbling through a nightmarish world of drugs and talking typewriters.
Ichi The Killer (Takeshi Miike, 2001)
Just as stunning as the combination of Burroughs and Cronenberg, there is no more frightening team of manga artist Hideo Yamamoto and horror director Takeshi Miike. Miike had just come off the success of his deeply disturbing masterpiece Audition when he began adapting Yamamoto's Ichi The Killer for the screen. Tadanobu Asano stars as Kakihara, the man who puts the "anti" in anti-hero. The tortures perpetrated by Kakihara are so extreme and treated with such detached humor that watching Ichi The Killer is something of an endurance test, even for veteran splatter-hounds.
Head (Bob Rafelson, 1968)
To round out the theme of bizarre collaborations, I've selected what may be the most ill-advised film ever made, Bob Rafelson's Head, a psychedelic exploitation of pre-fab rock band The Monkees. Rafelson wrote Head with none other than Jack Nicholson and the result is a completely nonsensical art film that manages to be both a parody of the sunny Beatles pictures of the era as well as shameless co-opting of late 60's counter-culture. It's a mess to be sure and was a terrible flop in its time, but Head is still a unique work of cinema.
Dead Ringers (David Cronenberg, 1988)
On the other end of the messed-up spectrum from Naked Lunch is David Cronenberg's 1988 psychological drama Dead Ringers. Jeremy Irons stars as Elliot and Beverly Mantle, twin brothers with a highly respected gynecological practice in Toronto. The brothers' strange sharing habits and lifelong co-dependence lead to (among other things) drug addiction and a shocking decline. The movie is inspired by the real case of the Marcus brothers, though the plot progression and set pieces are unmistakably inventions of Cronenberg. Dead Ringers isn't a nightmare from beginning to end like the rest of the movies on this list, but its ending is among some of the most epically disturbing in cinema history.