I've never read it, but someone mentioned about it in the comments of a novel I was reading and now I'm curious. Apparently its about a spider youkai, the owner of an inn, who wanted a mate and therefore did the deed with a reporter who came to his inn to stay for the night. At the end, worms came out of the reporter and the room was filled with all kinds of insects...
That kinda sounds like this manga. http://www.mangago.me/read-manga/bakemono_bl/mf/c006/ It is definitely not for everyone and I would advise against reading it but here you go.