Call of Duty: Ghosts zombie mode seemed inevitable. Last year's Call of Duty: Black Ops 2 featured an extensive zombie mode, a beefed-up version of the zombie modes found in Black Ops and World At War. They're super popular among fans, and for good reason. Killing zombies is fun. Mad fun. And if you think people are getting "over" the whole zombie thing it only takes one look at the Walking Dead's monster ratings and the hype surrounding Dead Rising 3 and Left 4 Dead 3 to know that the undead won't be dying anytime soon.

So far, we haven't heard anything about Call of Duty: Ghosts zombie mode but that's doesn't mean it's not coming, does it? Call of Duty: Ghosts does have "Extinction Mode" but that could mean anything. Plus, a new Instagram video is supporting the rumors from earlier this month that Call of Duty: Ghosts zombie mode is out and a new alien-based mode is in. Take a look:

The strange morphing skulls in the new Instagram video have some fans speculating that Call of Duty: Ghosts "Extinction Mode" will feature aliens and that the zombie modes of games past will become the signature mode for Treyarch. Infinity Ward is behind Call of Duty: Ghosts so there could be truth to that rumor, especially if Infinity Ward is looking for its own zombie mode-style gameplay to lure fans. And today's Instagram video isn't the only alien-skull clue leading fans to believe that Call of Duty: Ghosts zombie mode has been replaced.

A story on VGLeaks earlier this month pointed out the possibility of "Call of Duty: Ghosts alien horde co-op mode." The story is based on the "Extinction Mode" that has been spotted in the background during the menu selection screen in some recent gameplay footage as well as a list of Call of Duty: Ghosts achievements posted to Exophase. Here's the trophy list:

As you can see, the icon for the "Completionist" trophy has a rather unusual skull attacked to it. Look familiar? It looks a lot like one of the skulls featured in the Instagram video above. Obviously, we won't know for sure until infinity Ward gives us official word on what Extinction Mode is all about, but based on the skulls in the Instagram video and the trophy list it looks like zombies are out and aliens are in.

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