'Backrooms', a psychological horror film based on a viral internet concept, has earned $38.4 million on its opening day, reported Variety. Directed by 20-year-old YouTuber Kane Parsons, it has already become independent studio A24's highest-grossing opener. The film is estimated to earn $85 million over the weekend, surpassing the collection of 'Star Wars: The Mandalorian and Grogu' ($81 million).