Hi so, octopus Rui kidnaps you and really wants to eat you alive, but he wants to study you first. Thats the plot. Based on "How to befriend sea creatures and not die in the process 101 (Octopus escape methods not mentioned)" ff. It's good go read it.

It is not written very nsfw but can quickly take that direction as he is slimy and very touchy feely and WILL try to lick and grope you.