"Although it sounds painful, you feel no pain." This is one of the more bizarre sleep-related disorders i've heard of. My kid (6 yrs old) has been having night terrors and what sleep experts call "confusional arousals" for about a year now, off and on, and i'm both frightened and fascinated by them. Apparently they're common in children and run in the family — my wife had them when she was a kid too. Anyway, not quite as startling as Exploding Head Syndrome but curious nonetheless.