Fat Man (Fallout 3)

The Fat Man is a handheld tactical nuclear catapult found in Fallout 3.

Description
The Fat Man appears only in Fallout 3, and can be found in various places in the game. Because of its nuclear payload, it is by far the strongest V.A.T.S. enabled weapon in the game, perfect for taking out multiple enemies or heavily armored units - and in normal use, you'll be encountering both. The Fat Man has an estimated range of 150+ yards and will fall if shot in the air; be aware that the blast zone will be irradiated.

It should be noted that the Mini Nuke projectile is very heavy, and if simply fired straight ahead in a straight line, it will travel less than a couple dozen feet before falling to the ground and detonating (causing you to be caught well within the very damaging mini-nuclear blast). For best results, the Fat Man should be fired only in V.A.T.S. mode at high skill levels (which automatically compensates for the projectile's downward trajectory), or at an upward angle to catapult the mini nuke further so that it impacts at a further, safer range.

Item Locations
NOTE: This appearance of this Fat Man does not work if you have finished talking to Elder Lyons after being captured by the Enclave as it is the Lyon's Pride outside GNR battling the Super Mutants, but the Pride is waiting at the Citadel for you. Thus the dead Brotherhood of Steel soldier does not appear, i.e. neither does the Fat Man or Mini Nukes. (Only proven on 360 version) It also will not apear (in 360) if you visit the Jefferson Memorial before visiting GNR. It will not appear if, by any of the many ways, the normal GNR quest is skipped and Sentinel Lyons is not encountered.
 * You can find this gun right outside of GNR, as well, during the "Following in His Footsteps" quest by picking it up from a dead Brotherhood soldier. Using this method, one can acquire the Fat Man fairly early in the game. Note that this Brotherhood soldier is found by the fountain near where you fight with the Super Mutant Behemoth you encounter during this quest, along with 8 mini nukes.


 * A Fat Man can also be found in Evergreen Mills, in the basement armory of Germantown Police HQ (behind an average locked door), or at the Talon Company fort.


 * In the Armory at National Guard Depot, behind a door that requires a passcode, you can find the Experimental MIRV version of Fat Man which can fire only, no more or no less than, 8 Mini Nukes at once. This is no easy task, as all 5 Keller Family Transcripts must first be found.


 * One can be found at the end of the Old Olney Sewers( Along with Prototype medic armor) after battle with a number of Deathclaws.


 * A Fat-man and Mini-nuke may possibly be found on a Scavenger lying dead on the side of a brown car in a gas station (large red rocket) slightly east of Old Olney (the next square over in the map, bottom part of the square). Northwest of the Nuka Cola truck (with many Nuka-Colas and Quantums) may be a better land mark. This may be a random encounter, but the scavenger seemed to be positioned slightly off the trunk, as if the developer wanted you to see him as he fell out of it. The scavenger's inventory may also be randomized.


 * One can also be found in Fort Constantine Alongside the T-51b Power Armor and two Mini Nukes. You will need all 3 of the special keys from the You Gotta Shoot 'Em in the Head Quest to access the room.


 * One can also be found in the ruins of the White House near a skeleton. Next to the Fat Man is three Mini Nukes.  The White House can be accessed from a utility manhole south of the building on Penn Ave.


 * Flak in Rivet City has also been known to sell one at times.


 * Another can be found equipped by Talon Mercenaries in the Capitol Building during or after the fight with the Super Mutant Behemoth


 * A dead scavenger close to the center of sector h8v2 (at the boundary of leftmost and central mini-square in the map) carries a Fat Man and a Mini Nuke.


 * Shrapnel in Rivet City carries one in which you can provoke him into a fight where you can knock the Fat Man out of his hands.
 * One can be found even as early as completing the first objective in The Wasteland Survival Guide. One has been found where a Raider pulls the Fat Man out as a weapon.

Operation Anchorage

 * Towards the end of the last of the four new quests installed with this DLC four American Soldiers with T-51b Power Armor pull out Fat Men that can be knocked out of their hands and kept using the inventory glitch from Anchorage, thus adding 4 new Fat Men into the game.

NOTE: If you have a high enough sneak level these four Fat Men can be pick pocketed from the soldiers, while they are using miniguns(before you disable the pulse field). They will then revert to their previous behavior after disabling the pulse field, again pulling out 4 new Fat Men which you can then shoot out of their hands. (Unconfirmed)

Controversy

 * The name and image of this weapon are references to the Fat Man atomic bomb that was dropped in Nagasaki, Japan, ending World War II. Because of this, the weapon was renamed when Fallout 3 was released in Japan (Nuka Launcher). It is, however, still referred to as the Fat Man in dialogue.

Trivia

 * The launch mechanism of the Fat Man is pneumatic, coupled with the heavy projectile, this accounts for the short range of the weapon. This type of launch system was first pioneered by the British PIAT anti-tank weapon of WWII, where the projectile was launched from a similar cradle-like contraption using a mechanical spring system, which had the similar properties of short range and lack of accuracy. This system is known as a spigot mortar.
 * Fat Man was the codename for the atomic bomb that was detonated over Nagasaki, Japan, by the United States on August 9, 1945, at 11:02 a.m. It was the second of the only two nuclear weapons to be used in warfare and was the third man-made nuclear explosion. The name also refers more generically to the early nuclear weapon designs of U.S. weapons based on the "Fat Man" model. It was an implosion-type weapon with a plutonium core.
 * The weapon was made in the pre-war era as it appears in the Operation:Anchorage DLC. It is used by a squad of Powered Armor Soldiers to destroy a large gate of the chinese outpost.
 * The Fat Man is likely based off of an actual weapon, the M-388 Davy Crockett, developed by the United States during the Cold War.