Anime anatomy wise she Is showing you her pussy. Science whore wise, she is showing either her pussy of her mouth. From what I do know is that an octopus has a beak. So to me that is a pussy
The artist was an anonymous 2ch user who posted the 391st comment on the 69th "Monster Girls” topic/thread of 2ch Half-Width 2D Board at September 27, 2009 04:11.