Okay, so one of the most famous artists in Japanese history is Hokusai, who made THIS picture you have probably seen before:

However, I totally randomly found out this evening that in 1820 he also created the first ever picture of a woman getting tentacle raped, called "The Dream of the Fisherman's Wife."
You'd
better believe this is
NSFW:
spoiler (click to show/hide)
I find it incredibly amusing that something as horrific as tentacle rape has a well-defined origin point from one of Japan's greatest artists.
(This content stolen from a Making Light thread about works that could be mistaken by a casual observer as part of the Cthulhu mythos.)