Physicist Mounir Laroussi’s “plasma pencil” generates a “cold plasma,” which can be used to kill germs. In the future, it might be used to destroy tumors without damaging surrounding tissue.

When he turns the pencil on, it blows a high pitched whistle as a glowing, blue-violet beam about 2 inches long instantly appears at one end. Stick your finger in its path and you only feel a cool breeze, but the beam is powerful enough to blast apart bacteria that’s crawling on your skin.

It uses a stream of helium gas laced with oxygen that is blown between two copper electrodes. Electricity pulses through the electrodes thousand of times in a second to split the oxygen molecules into single oxygen atoms.

Laroussi, an associate professor at Old Dominion University, hopes the beam will soon find its way into doctors’ and dentists’ offices.