Ever woken up, but couldn't move a muscle? You're not alone. It's called sleep paralysis and it can be really scary (video)

Call a Jesuit to check your place out.

In Finnish and Swedish folklore, sleep paralysis is caused by a mare, a supernatural creature related to incubi and succubi. The mare is a damned woman, who is cursed and her body is carried mysteriously during sleep and without her noticing. In this state, she visits villagers to sit on their rib cages while they are asleep, causing them to experience nightmares. The Swedish film Marianne examines the folklore surrounding sleep paralysis.

Folk belief in Newfoundland, South Carolina and Georgia describe the negative figure of the hag who leaves her physical body at night, and sits on the chest of her victim. The victim usually wakes with a feeling of terror, has difficulty breathing because of a perceived heavy invisible weight on his or her chest, and is unable to move i.e., experiences sleep paralysis. This nightmare experience is described as being "hag-ridden" in the Gullah lore. The "Old Hag" was a nightmare spirit in British and also Anglophone North American folklore.

In Newfoundland, it is known as the 'Old Hag'. In island folklore, the Hag can be summoned to attack a third party, like a curse.

In Iceland folk culture sleep paralysis is generally called having a Mara. A goblin or a succubus (since it is generally female) believed to cause nightmares.