This one movie I saw on SBS a while back, I'm so pissed I never found out it's name (if someone can tell me I would hug you IRL). Its set in a single cell in an insane asylum. The main character was put in there by his lieing wife so she could divorce him and take his money. The other 3 cell mates consist of a big burly cannibal who killed women to eat their... well female specific parts and who was slowly getting plastic surgery to become a woman (only got massive cleavage before he was caught), a really thin, introverted, autistic guy who no one knows what he did to be there and a member of a mystical cult that murdered his entire family. Anyway they find a book of rituals from the cult one of the cell mates was a member of and they have a massive argument over whether to use it or not. Eventually they throw it out the window and destroy it but new editions of the diary/ritual book keep making their way back into the cell. The book defends itself too and causes weird things to happen. Like the thin guy eats some of the pages and he gets lifted into the air and all his body parts start getting twisted and crushed until every bone in his body is shattered and all his skin is torn. Eventually they all kill each other and only the main character survives and completes the ritual only to find the benefit of it is also a massive curse (to have your wish fulfilled you are killed and your spirit is cursed to being trapped).
I wish I knew what it was called. It was a creepy movie.
Edit: It wasn't english if that helps. I had it turned down low to catch only the music and subtitles.