It’s the middle of the night. You wake up with a start. There’s a presence in the room watching you. You sense that it is evil. But you are paralyzed and powerless. It’s your worst nightmare – Or is it? In this week’s Vox Humana Michele Ernsting explores the strange and surprisingly common condition of sleep paralysis with Dr. Al Cheyne, a leading expert on the subject and several victims of “night frights”.