In an era of found footage horror films, Sinister is a film that's actually about finding footage. That doesn't make it unique in its genre by any means, but there's something about tweaking the formula just so in the era of Paranormal Activity that makes key moments in Scott Derrickson's film really hit home. Each of the "home movies" Ellison (Ethan Hawke) watches throughout the film is disturbing in its own way, and they're all united by their grainy Super 8 aesthetic and the sense of voyeurism that builds to slaughter, which itself calls to mind classics like Black Christmas and Halloween. The lawnmower sequence, though, has that extra little ingredient of shock. It's devoted so much to the buildup, to following the mower as it rolls toward its destination, that you almost forget you're about to see something horrible. The abruptness of it, and the lack of gratuitousness in the payoff, work together to create squirm-worthy horror in your head.