Shadow People

Last night, in the middle of the night, during one of my deep-sleep cycles, I awoke just enough to see a black shape hovering over my chest. It could have been on my chest, but I say hovering because I felt no sensation of it physically contacting me. It was fairly dark in the room, with some light coming in from the window and my open bedroom door. I was still partially asleep, but I immediately realized this was something that shouldn't be there. It was completely black, and obscuring more than a third (maybe half) of my field of view.