This was the decade that slashers became even more meta thanks to filmmakers like Joss Whedon, who found a new way to honor — and troll — horror fans. “Being haunted” no longer became contingent upon moving into a spooky house: As It Follows taught us , it could also be a terrible side effect of your most recent hookup. The larger-than-life dystopian society of The Purge movies — in which all crime, including murder, is legal for one day every year — got closer to reality as each subsequent film in the franchise leaned further into America’s political division.