The Lightmass bomb is a weapon that was intended to be used to destroy the Locust Horde. At the beginning of Gears of War, the COG do not have enough tunnel data to effectively use the bomb. Originally, Victor Hoffman wanted Delta Squad to retrieve the Resonator and deploy it underground to gather tunnel data. However, the resonator did not give enough data, but Delta Squad did manage to find a Geobot with additional tunnel data. After getting the tunnel data, Delta boarded a train carrying the Lightmass Bomb and activated it, after defeating General RAAM and his Locusts. However, in the final scene, the Locust Queen can be heard talking and it becomes apparent that some Locusts are still alive. It is also said in one of the Gears of War 2 collectibles that the Light Mass Bomb is the purpose for why the Rift Worm is awakened and starts too sink the cities.