Laser Kill
From Halopedia, the Halo wiki
A medal awarded in the Halo 3'' Beta for killing an enemy with the Spartan Laser weapon, awarded for any kill with the Laser due to the unwieldy charge time and precise accuracy it takes to destroy a target with the weapon. When killed by the Spartan Laser in Halo 3, it says YOU WERE LASERED BY (Opponent's Name Here).
