Last December's The Darkest Hour wasn't exactly our favorite movie — but it did have a few really neat visuals, including the way the invisible electric aliens killed people: The Shred. For a movie that saved on its budget by having aliens that were invisible most of the time, Darkest Hour did find a cool way to make the aliens' presence felt. The Shred disintegrates people almost instantly, with tendrils of electric force, and every death looks different. Check out an exclusive look at the making of this effect, from the Darkest Hour DVD and Blu-Ray. I love the guy who says, "We had to visualize [the aliens shredding human flesh]. Is it like a wood chipper? Is it like a belt sander?"

The Darkest Hour is out on DVD and Blu-Ray now. Just be sure to put a Faraday cage on your cat!