I bought one of the blue lasers they use to blast the mosquitoes. It's a 1 watt laser. Ridiculously powerful. It will light you on fire and burn holes in you. It comes with a warning: It will seriously blind you instantly. It will burn your house down, from 20 miles away. If you mount it on a gun, you can shoot a bad guy, then cauterize his wounds. In my evil empire, I will mount them on sharks, to deter sea-borne attackers.