The mara is the Scandinavian version of a nighthag. She is a spirit being who rests on the chest of her victims to weigh them down. She can seep through any crack in a room, including a keyhole. She is said to "ride" her victims, but she sucks peoples blood while riding. The spirit of a sleeping woman can slip into the night and become a new mara, if the woman is cursed or wicked. Sometimes, she will ride a horse by grabbing onto its mane. The manes will twisted into "marelocks" and the poor horse will be exhausted after what happened last night. If you think a woman is a mara simply face her down and tell her, "You are a mara", three times over.
- The word "nightmare" comes from "mara", it is because after the mara has riden her victim the person will feel her presence in the form of tormented dreams, or nightmares.