Unfriended
This 2014 hit—which takes place entirely within the boundaries of a computer screen, paving the way for 2018’s Searching and similar films—is truthfully more “internet horror” than “social media horror,” but it all begins with a pair of YouTube videos: one showing high-schooler Laura being humiliated at a party, and a subsequent clip capturing her suicide. One year later, someone claiming to be the dead girl pops up online—and weaponizes Skype, Facebook, Instagram, and other sites as a way to get vengeance on her tormenters. Streaming on Netflix.
