Mara

Criminal psychologist Kate Fuller is assigned to the murder of a man who has seemingly been strangled in his sleep by his wife and the only witness is their eight-year-old daughter, Sophie. As Kate digs into the mystery of an ancient demon which kills people in their sleep, she experiences the same petrifying symptoms as all previous victims and spirals through a chilling nightmare to save herself and Sophie before she dares fall asleep again. (imdb.com)

Mara is a 2018 American supernatural horror film directed by Clive Tonge in his feature-length debut and written by by Jonathan Frank. The film stars Olga Kurylenko as criminal psychologist Kate Fuller, who investigates the murder of a man and is haunted by demon who kills people in their sleep. The film also stars Craig Conway and Rosie Fellner. Tonge and Frank based the film's story on conditions and mythology surrounding both sleep paralysis and Brugada syndrome.