The Flakvierling (Flugabwehrkanone vierling 38, literally "anti-aircraft defense cannon quadruple (model) 38") is an anti-aircraft weapon encountered in the WWII Call of Duty games as well as a brief appearance in the zombies map Zetsubou No Shima in Call of Duty: Black Ops III, often as a mission target and rarely as a player-controlled fixed weapon. In missions, they are often simply referred to as "flak guns."