The military have their own version of the old green laser pointer prank, one that can blind people 4km away (even if, at that distance, the blinding is temporary). They use it to hail and warn enemies trying to advance.
The weapon - which is technically a "long-range visual deterrent laser device for hail-and-warning applications" - is called the Glare LA-9/P, and it's quite dangerous, even while it has a security system to avoid eye damage. That's something that didn't stop it from blinding dozens of soldier during the Iraq war, exposed to friendly dazzling. [BE Meyers via Danger Room]