Most commonly used in the "Call of Duty" game series. Certain perks allow individuals to have an increased amount of health, which in turn makes them harder to kill. Stopping Power, FMJ (Full Metal Jacket), Deep Impact, Grenades and other explosive devices have no affect on these jackernauts!
see also: cocksucker, noob
Player 1: "I can"t seem to kill these cocksuckers!"
Player 2: " That"s because they're all running around with
fucking jackernaut on"