http://en.wikipedia.org/wiki/The_Entity
That reminds me, too, of the invisible rape scene in Hollow Man. I remember thinking Hollow Man was a fairly comical, fun little film and then in the middle of it AN INVISIBLE RAPE SCENE. That actually has to be the most disturbing scene in a mainstream film; just the IDEA of it. And that film won awards! (for special effects, though) Insane.