Boy, that Shia LaBoeuf really wants to show people how dark he is, huh? It doesn't get too much darker than "Maniac," the short film he directed and released on Halloween, starring Kid Cudi and Cage. In it, the two kill eight people each for no discernible reason, with a variety of weapons including shotguns, knives, and in one particularly creative slaughter, a dog leash. The entire time, they are being followed by a camera crew (also for no discernible reason), until the duo turn the cameras on them and decide to kill them as well. (This one has a discernible reason, at least—Cage and Cudi agree that they're getting annoyed with the crew following them. Not terribly logical, but discernible at least.)
Oh, and the whole thing is in black and white. And it takes place in France and everybody speaks French. And it doesn't feature or appear to have anything to do with the actual song "Maniac" from Cudi's Man on the Moon II. Why? You didn't really just ask why, did you?