Australian cinemagoers who had taken their children to watch\u00a0Peter Rabbit\u00a0were left ashen faced after the projectionist mistakenly showed the trailer for terrifying new horror film\u00a0Hereditary.\r\nThe Sydney Morning Herald\u00a0reported that Event Cinemas in the Perth sububurb of\u00a0Innaloo accidentally showed a preview of the film \u2013\u00a0billed as\u00a0\u201cthe scariest horror in years\u201d \u2013 which struck panic in both children and parents gathered in the audience.\r\nNoticing the furore, cinema staff eventually turned off the trailer and apologised to customers by offering them complimentary tickets.\r\n\r\n\u201cIt was dreadful,\u201d one audience member recounted. \u201cVery quickly you could tell this was not a kid\u2019s film. Parents were yelling at the projectionist to stop, covering their kids\u2019 eyes and ears. A few went out to get a staff member but she was overwhelmed and didn\u2019t really know what to do. Some parents fled the cinema with their kids in tow.\u201d\r\nEvent Cinemas is currently investigating how the error was made. \u00a0\r\nHereditary\u00a0stars Toni Collette, Gabriel Byrne, Alex Wolff and Ann Dowd. It follows a woman\u2019s unravelling of increasingly terrifying secrets about her family\u2019s ancestry following the death of her mother. The film picked up steam after its premiere at Sundance Film Festival where it has since been deemed\u00a0\u201cthe most traumatically terrifying horror movie in ages\u201d. It will be released in the UK and US in June.\r\nSome have theorised that the mishap could have been a publicity stunt for the film\u2019s release, but\u00a0The Independent\u00a0could not verify this.