After premiering at the Toronto Film Festival last year and releasing at the beginning of May, it has become a word-of-mouth phenomenon over the last two months with fright-loving Gen Z audiences in particular.Its success has catapulted 26-year-old Barker from a YouTube video creator into Hollywood's A-league with a first feature-length film that cost just $750,000 to $1 million to make."In terms of the ratio between the worldwide box office and the production budget, 'Obsession' is going to be the biggest success of all time, which is extraordinary," Bruce Nash, founder of industry-tracking website The Numbers, told AFP.With ticket sales of around $430 million worldwide, it has already overtaken the 1999 supernatural thriller "The Blair Witch Project", which made around $250 million on a full budget of $600,000, according to Nash. In absolute terms, Hollywood mega-hits such as the "Avatar" films, "Frozen" or "Titanic" made more money but with blockbuster budgets several hundred times the one available to Barker. - Burgers to big screen - The Alabama-born director's success at the box office has surpassed that of the other remarkable horror hit of the year -- "Backrooms" by 20-year-old Kane Parsons, which has earned $360 million with a budget of around $10 million.