You are on the dark side of Anime industry again! You will find most disturbing anime in this list, that are not for faint heart people! I suggest not watching it but here you go!
1. Midori: Shoujo Tsubaki
After losing her parents, young flowers selling Midori is put up by a fair-ground group. She is abused and forced into slavery, until the arrival of a magician of short stature, who gives her hope for a better future.
2. Cat Soup
Cat Soup is an experimental 2001 Japanese anime film directed by Tatsuo Satō, inspired by the work of manga artist Nekojiru