BFG9000

The BFG9000 is a weapon found in Doom, Doom II, and Doom 3 (although the BFG9000 found in Doom 3 shares only the name.) The BFG9000 appears as a large, solid metal gun that fires big balls of green plasma. The most powerful in the game, it is capable of destroying nearly any player or enemy with a single hit. Most subsequent first-person shooters implemented similar weapons, but few of them were quite as notorious as the BFG9000.

The abbreviation BFG stands for "Big Fucking Gun", as explained in Tom Hall's original Doom design document (Section 14). Other explanations of the name that circulated before the document was made public include "Big Fragging Gun" and "Big Fun Gun". In the paperback novelization of Doom published in 1995, the characters refer to the BFG as a "big freaking gun".

In older versions of Doom, the BFG was a "billion fireball gun", shooting a lot of small green and red fireballs. It was called the BFG 2704.

Technical
When firing the BFG9000, there is a pause of exactly 6/7 of a second (about 857 milliseconds) before a green plasma ball is ejected. If the plasma ball hits a solid object, it explodes and causes between 100 and 800 points of damage on that object. After a further pause of exactly 16/35 of a second (about 457 milliseconds), blast damage is calculated: 40 invisible rays are emitted by the player in a cone-shaped area (about 45° half-angle) in the direction the plasma ball was fired (if the player has turned around, the direction of the blast damage rays don't change - they are still traced in the direction of firing of the original plasma ball; if he has moved around, their origin changes). Each ray causes 49 to 87 damage points if it hits a solid object in its range of 1024 map units. Therefore the minimal damage of the weapon is 49 points of damage (if an object is hit by one ray and not the plasma ball) and hypothetical maximal damage of the weapon is 800 + (40 &times; 87) = 4280 points of damage (if the plasma ball hits an object for full damage and all 40 rays also hit the object for full damage). However, that much damage can never actually be inflicted due to the periodicity of the simplistic pseudorandom number generator used by the Doom engine.