Follow-Up:
I've had this happen twice. Once in my early twenties, and again a couple of years ago. Both times I was sleeping on my stomach, which is not my usual position. Both times, I awoke to a roaring sound. Not like the roar of a crowd; more like the white noise of a radio not tuned to a station, with the volume turned up high. Both times I felt a PRESENCE. It was something that was much more powerful than me, and it wanted to do me harm. My eyes were open, and I could see the room around me, as far as that goes. I couldn't move my head or any other part of my body, but my eyes were darting around. These were not just nightmares. If they were, I haven't woken up from them yet. I capitalized the word "presence". I did that for a reason. I felt that the being in the room with me was so much more powerful than me and so evil that I was completely helpless. The first time it happened, I was convinced that my enemy was a witch, complete with a black pointy hat. The second time, I knew that it was nothing less than a demon come to claim my soul. That time, I said the Lord's Prayer aloud. (Or I tried to. I would like to hear a recording of the moans and grunts I emitted.) The experience ended when I finished the prayer. I wish I knew more about this phenomenon. Why the roaring noise? Why the sense of overwhelming evil? Part of this may be due to the paralysis: "I know I can move if I want to. I can't move! Something powerful must be preventing me!" Please do not link to any UFO site because you've had this experience. It is unusual, but not abnormal. I imagined a witch and a demon. You may imagine an alien. It's all in our minds. Look into this, as I am trying to do. If you imagine an alien, fine. That's how your brain is choosing to interpret this quite disturbing phenomenon. It makes more sense than my imagining the Wicked Witch of the West. Don't let it become more important than what it is: a brain fart. Aren't our brains wonderful, that their farts spawn tales of witches, demons, and alien abductions?