Caligula
This film was made to accurately attempt to depict the life of Caligula, one of the rulers of the Roman Empire. This was originally political satire but turned into something much more unsavory. One of the original directors disavowed the film, and it is banned in several countries.
The Human Centipede II
The sequel to the cult classic The Human Centipede does not shy away from gore, disturbing imagery, and torture. A deranged fan of the original film follows in the footsteps of the German surgeon who got the ball rolling, this one is literally four times as disturbing as the first.