The Annihilator is available when reaching Tyhrranosis for 150,000 bolts. With use, it can upgrade to the Decimator, which releases heat-seeking mini-rockets once the main rocket is detonated. The Decimator is described as being powerful enough to pierce Carbonox Armor. It can be upgraded to the Mega Decimator from any vendor in challenge mode for 580,000 bolts.
The Annihilator is a long silver, blue and orange weapon with three metal and blue highlights on its barrel and a fairly wide nozzle. It launches very rapid rockets at enemies. The Decimator is larger and thicker, with three pure metallic highlights. Large blue highlights are also featured on the weapon.
The Annihilator is at its core a simple rocket launcher, though with a high rate of fire, high speed and solid range. Its damage is not initially outstanding, but holds up for the entirety of the game, and is strong against bosses. It particularly serves well against groups of enemies, due to its blast radius and additional mini-bombs and mini-missiles it releases upon impact with upgrades. The Annihilator has good ammunition, blast radius and damage, making it a very versatile weapon and useful against all threats and throughout the game.
The V2 Annihilator rocket drops scattering bomblets on detonation. At V3, these mines home in on enemies. V4 gives it an additional lock-on mod which makes it easier to use against larger targets. At V5, the rockets release mini-rockets rather than bomblets, which deal even more damage, and can hit flying enemies as well.