The Fat Man is a shoulder-fired nuclear catapult in the Fallout universe. The explosive projectile is a drastically underpowered version of the atomic bomb that can explode approximately 30 meters in front of the character and have no negative effects. Ammo is limited, and to no surprise considering the weapon uses "mini nukes" as the ammunition. There is a variation of this weapon called the "Experimental MIRV" that shoots 8 mini nukes at one time. This alternate version is effectively the most powerful weapon in the game, as well as the most awesome and unnecessary.