Have you ever had a nightmare where you were aware you were dreaming, but were unable to wake yourself up, unable to move even unable to breath? You may have met the "The Old Hag", a phenomenon documented around the world that scientists call Sleep Paralysis.
The experience varies from person to person. Some people see a woman't face in the distance but can't pick out her features. The dreamer usually senses something is very wrong and becomes anxious, as the figure draws nearer they realize it is an ugly old crone. When she finally reaches the dreamer she slowly crawls up over the person's body and straddles their chest; slowly crushing it, stopping their breath. The dreamer is hyper aware of what is going on; the fact that they are sleeping, that this is not really happening, but yet they sense the evil, and can feel her leathery touch as breathing becomes a struggle.
In David J. Hufford's book The Terror that Comes in the Night he writes that you can call the Hag by reciting the Lord's Prayer backwards.
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