A look of pure hatred given to someone that has seriously wronged you. When done successfully, it should appear as if daggers or flames are coming out from your eyes. The most fierce of death glares will even reduce people to tears, or make them move away from you in fear.
Bob: Man is that girl a jerk!
Girl: *death glare*
Joe: Dude, look at the death glare she's giving you you better back off.