Amputation the manga. It starts as an edgy 4-page??? yuri romcom, just to turn into the worst horror story I have read this year. To the mangas credit: It is very funny. It is not on "The friend-eater game" level but it fits on that spectrum. Despite the story being unhinged and crazy, it was filled with cliche characters and a very generic lesbian relationship. Like the characters, the story also lacks depth and common sense, but this is probably what you wanted to hear anyway. Don´t expect to much gore. There is blood, but besides that; no torture or rape (emplied in a backstory) and definitly nocomparison to killing stalking.
Have a nice day :)