19. August Underground's Mordum (2003)
Truth be told, the only assurance that the August Underground movies are legitimate is that they exist on both IMDb and Rotten Tomatoes; otherwise, it might be safe to assume that these super-low-budget nightmares were actual snuff films.
The second film of the series, Mordum, may just be the most extreme. It opens with a scene that involves a girl having sex with her brother. This girl is the main character’s girlfriend. Things just get more wicked from there.
The list of atrocities committed in this film are nearly endless, but here's a small sampling: A girl repeatedly pukes on two other girls, forces them to eat the vomit, and then the two girls are slaughtered. A man is forced to castrate himself with scissors, and the severed penis is then fellated by a girl. To top this scene off, the guy's helpless, bound girlfriend is then raped with the severed penis (before being killed, of course). A guy has sex with the rotting corpse of a very (very) young girl in a bathtub. And so on and so forth. What else really needs to be said about this one?