BFG 9000 — Fucking or Freaking?

The BFG9000 is a weapon found in the computer games Doom, Doom II, and Doom 3 (although the BFG 9000 found in Doom 3 shares only the name.)

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".