The Old Hag is a witch of sorts that brings nightmares. Resembling an ugly old woman dressed in black rags, the Hag sits on people's chests while they dream and sucks their breath out. The victim then experiences terrifying nightmares, and when they wake they find themselves unable to move under the weight of the Hag.
Sleep paralysis is a condition in which a person becomes conscious before their body exits the REM state. During sleep, the body enters a natural form of paralysis to prevent the sleeper from moving around too much, but when the sleeper wakes too soon they enter a frightening state in which they are unable to move. Because of the way the lungs slow during sleep, the alert person is unable to get the proper quantity of oxygen and feels as though their chest is being pressed down.
Alongside sleep paralysis are often vivid nightmarish hallucinations, which present the person with a terrifying scene. These hallucinations may be auditory, tactile, and/or visual and seem incredibly real.
- A person who looks weary may be called "hag-ridden" or "haggard."