Ever since the release of the iconic end-game mode in "Call of Duty: World At War" was released, users have come to expect a new mode of Nazi Zombies (or just "Call of Duty: Zombies" at this point). However, that game mode was not a part of any of the Modern Warfare games made by Activision. Instead, the Zombies franchise was reserved for Treyarch's "Blacks Ops" lineup of "Call of Duty" games.

Now it seems that the iconic end-game monster fighting mode has found its way into the upcoming "Call of Duty: Ghosts." It must have taken Activision a while to come up with some kind of monster that is socially acceptable to murder in mass without mercy, but it appears it has settled on Aliens.

According to IGN, a clutch of screenshots of the long-rumored sci-fi themed co-op experiences called "Extinction" mode appear to have leaked online, just ahead of its official reveal.

The images were posted online by Imgur user Smtkz. The collection of 17 unverified screenshot suggest the mode is all about taking on a brand new alien threat and destroying its hives. To further lend credence to these rumors, a list of the "Call of Duty: Ghosts" achievements leaked online a while back which, for some, verified the Extinction mode's existence. The full list can be found HERE, it includes several hints such as "Extinction challenges."

Activision has confirmed the Zombies replacement with a teaser video on its Instagram page, featured HERE. It looks like alien monsters will in face replace undead creatures as the stocking-stuffer game mode for the upcoming "Call of Duty: Ghosts."

Tell us what you think about an alien fighting game mode in the new title? Are you going to miss zombies or have they gotten kind of old for you? Comment and share your thoughts with us below.