The Big Fucking Gun (or more politely, Big Freaking/Fragging Gun) found officially in all of the high-profile
id Software games like Doom and Quake. Fires a very large
green ball of man-made lightning and then upon impact, the weapon instantly releases a huge spread of energy to anyone that the BFG'er is facing. (Despite how extensive this definition is, it is loose.) In Quake II, the ball of energy will shoot lasers a certain distance for some additional pain.
Newbies hate the weapon, but some veterans consider the BFG a
thinking man's weapon (in deathmatch)because of its strange behavior, slow firing rate, and high energy drain.