There are legends from around the world of a creature that comes to you at night and sits on your chest, sucking away your life force. The incubus, the succubus, the old hag — people really report these experiences, but how does science explain it? Dr. Brian Sharpless, co-author of the new book Sleep Paralysis: Historical, Psychological and Medical Perspectives, joins us to discuss the terrifying phenomenon.

READ the episode notes