Kane Parsons ' leap from YouTube creator to Hollywood filmmaker has officially turned into one of the biggest box office success stories of the year. Backrooms , the feature adaptation of Parsons' viral internet horror series (itself based on a 4Chan post ), is on pace to deliver the largest opening weekend in A24 history. The film pulled in approximately $38 million on Friday, alone and is now tracking for an estimated debut between $80 million and $90 million domestically. The projected haul would shatter the studio's previous opening-weekend record set by Alex Garland's Civil War , which launched with $25.5 million in 2024. Produced on a reported $10 million budget, Backrooms centers on a struggling architect, played by Chiwetel Ejiofor, who discovers a gateway to a seemingly endless maze of eerie rooms hidden within the furniture store he manages. The film also stars Renate Reinsve and Mark Duplass, while James Wan, Shawn Levy, and Osgood Perkins are among the producers attached to the project.…