To electrify a metal door handle would I need one connection or 2?

I am making a prop for a movie. In the movie the bad guy makes a device that sticks to a door and electrifies the door handle so that anyone that touches it gets shocked. In order to do this would I need one live wire to the handle from the battery or would I need one live and an earth? I automatically went opted for 2 cables like jump wires but don’t want to get it obviously wrong. Also is there any movie where such a thing has been made before?