this is exactly where the word “nightmare” comes from. In old European folklore (Germanic, Norse, and Slavic traditions), a “mare” or “night hag” was believed to be a real spirit that sat on a person’s chest while they slept. People used this to explain terrifying dreams, the feeling of being unable to move, and the sense that something heavy was pressing on them at night — what we now call sleep paralysis. The mare was said to sneak into homes through cracks or keyholes, climb onto sleepers, an