lasers.
Flying turboprops around Europe, I have had a green laser painting my aircraft twice. First time was from around 10 miles out in front on our 1'o'clock, as soon as I saw the twinkle, I called it and stuck my head below the glare shield. Flying IFR on a transition has its benefits. Second time was very close to us on our right side, so again head out of the way with something solid between us and the source. Both times at night.
I'd love me a GAU-12 slaved to a laser receiver to teach these guys a one-time lesson in how funny we think it is.