Extermination

Extermination is a spree medal awarded in Halo 3 Multiplayer for getting at least an overkill on the opposing team that results in all the team being dead. It is represented by a gray cross with a red skull. This medal is only awarded if the entire opposing team is exterminated before any of them respawn.

This medal is extremely hard to get on purpose as you rarely find all of the same team together and it is hard to stay alive killing at least four enemies within four seconds, preventing any of them to respawn.