Quite simply, the experience of sleep paralysis sounds too crazy to be true. When it occurs, which it does with surprising frequency, the victim often questions his or her own sanity. It is not uncommon to ascribe the experiences to demonic possession, aliens, and any number of otherworldly phenomena. What exactly is sleep paralysis? Learn about this unusual experience and what science tells us about the likely cause. Discover more in this Huffington Post article by Dr. Peters.