A grenade kill, where the thrower of the grenade is dead before their victim. Often, but not necessarily the grenade thrower kills their assailant - resulting in a sort of satisfactory stalemate. Term originates from UK online gaming community of late 90's early 00's, in particular "Counter-Strike" and "Halo: Combat Evolved". (Halo was originally played online via the system link facility, directly to another machine over the internet. Halo was never updated for proper Xbox Live online play)
"I was killed, but I got a quality death grenade!"
"Death grenade! I don't need to be alive to own you bitch!"