Thunderstorm (achievement)

Thunderstorm is a Halo 3 Campaign Achievement. It is earned when the player finds the Thunderstorm Skull. This Achievement gives 10 Gamerpoints to the player.

It is represented by a blue circle with a skull in the middle. The skull has a thunderbolt on its forehead.

Effect: "Field promotions for everyone!" -- Upgrades enemies to their stronger versions.

Related Links

 * Halo 3 Achievements