Most Horrifying Scene

** Spoilers **

I've given this film a little more thought, and I thought it would be interesting to hear opinions from others about the most horrifying scene.

When I first saw the film, I thought the worst part was the death and processing of the guy under the black floor, with the attempted rape and immolation being a close second. And while I still think those scenes are very hard to watch, I am beginning to think that maybe the lovemaking scene is worse. I say this because it seems to me a pretty awful thing to be attempting to have sexual intercourse with something that looks human, but is, in fact, quite alien. I guess I can understand from what I have intuited about SJ's character that she/it is proceeding from innocent motivations at this juncture of the film (trying or at least experimenting with what it means to be human), but still, from the guy's perspective ... ugh. Has anyone thought of it this way?

The intellect is cleaver; it discerns and rifts its way into the secret of things