Wikipedia
is a Japanese erotic horror manga series written and illustrated by Toshio Maeda and a series of original video animation (OVA) anime releases.
Urotsukidōji was created by Toshio Maeda in 1986 and was a huge departure from his earlier works in that it mixed erotica with dark humor and the supernatural. He was commissioned to do the series for Manga Erotopia, a pornographic manga magazine published by Wani Magazine that deals mostly with avant garde stories. Maeda was picked because of his artistic style which paid incredible attention to detail and for his ability to tell rather good stories with complex plots, unlike most erotic manga artists at the time.
Although the manga would grow a cult following, it was the anime which became notorious. Hideki Takayama took great artistic liberties with the Urotsukidōji story, mixing elements of horror, violence, and sadistic scenes of rape not present in the original work. Maeda himself stated in an issue of Playboy Japan that he found the anime to be repugnant, cruel and sadistic, yet brilliant. He also said he admires Takayama's take on his vision. The anime series is most famous for being the first in the tentacle rape genre, though only one scene in the first OAV actually contains any tentacle rape. Tentacle rape was not present in the Urotsukidōji manga but was featured in a series that he would publish years later called Demon Beast Invasion. Takayama was incredibly influenced by this work of Maeda's but thought that the Urotsukidōji story was stronger.
In an interview as to why Hideki Takayama chose to tell such a violent and sadistic story he said "There is nothing that arouses a stronger response in human beings than either sex or violence. A mixture of the two is very powerful indeed." Today Urotsukidōji, as well as its later sequels, are infamous, not just in Japan, but in the rest of the world as well. According to The Erotic Anime Movie Guide, it is the most recognized adult anime in the world. It was number 72 in Channel 4's 100 Greatest Cartoons.