its on discovery I think... its featured on a car where a would-be carjacker would try to steal your car at gun point. The car driver would simply arm and step on a special pedal. From under the doors, 5 to 10 feet of flame will come out, fed from a LPG tank hidden somewhere in the car. The device is only good if you are in the car to activate it.

The fastest way to give a carjacker a hot foot!