The music video for Serj Tankian's "Empty Walls" features the lead singer parading around a Circus of Fear with a bizarre, sociopathic look on his face, wearing a Svengali-esque costume, while various small children play happily...or, according to some viewers, reenact the War on Terror; with one kid throws a model plane into another's jenga tower, one drives a car into a building with a confetti "explosion", and everyone in the play house gets gunned down with silly string. Pretty creepy.
Another video for a song entitled "We are One" featuring both himself and experimental guitarist Buckethead, which depicts the stories of the various dead things that Buckethead uses to make a Frankenstein's Monster which, when reanimated, does the same to him.
And then there's the rest of his videos. Check the end off the official "Sky Is Over" video, or most of "Lie Lie Lie" (which he says was supposed to be lighthearted!), and 'The Unthinking Majority' is almost bizarre. And all with that creepy feeling...