I don't mean a bad dream, but the stereotypical experience some scholars call "the Old Hag" where you wake up unable to move, a malevolent entity enters your room and tries to smother you by kneeling on your chest. I have heard that up to something like a quarter of the population has had this, and often not known that others have as well. It is possibly more common among imaginative people (like us). I once was in bed and wondered "what would it feel like to suffocate" and suddenly could not breathe...I shot bolt upright. Perhaps this was a very abnormal nightmare?
Anyone want to describe if they had this experience? It is something which always fascinated me, how different people in different cultures can have the same bizarre experience and not even know of others having the same one.