Exterminator
From Halopedia, the Halo wiki
Exterminator
Exterminator is a Halo 3 Meta-Game Achievement. It is earned when the player earns 15,000 points while playing the meta-game on Floodgate. This Achievement gives 10 Gamerpoints to the player.
It is represented by a blue circle with a horned medieval medium-helm. The level is aptly named because it is the first level to feature the Flood in Halo 3, and first lets you 'exterminate.' This is most likely the hardest level to get 15,000 points, it is the shortest level, the Arbiter and elites steal valuable points, and has fewer enemies.
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