Modern Warfare's multiplayer modes allow player characters to wear functioning wristwatches with different functionalities, as revealed to Game Informer by Geoff Smith, Multiplayer Design Director at Infinity Ward.

We put in a watch pretty early on; one of our coders got really excited about it and over a weekend synced up a dev kit to have the actual time on the watch, so it actually tells the real time from your kit. Then that just kind of kept growing into more and more madness.

The original idea belongs to Joel Emslie, Art Director at Infinity Ward, who went on the explain that there's an optional Tamagotchi-like add-on to it.

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This little thing on your wrist, every time you get a string of kills, it goes, ‘Ya-ta!’ and it makes a little noise, then you look at it, and it evolved out of an egg. The TamaGUNchi is fed by the player’s performance in multiplayer. It’s just this little active wristwatch thing. If you don’t take care of your TamaGUNchi, it will rot and die.

Taking care, in this case, translates to maintaining a healthy kill-to-death ratio when playing Call of Duty: Modern Warfare in multiplayer.

It's certainly an odd addition for a game that otherwise strives so much to depict war in a realistic fashion, but then again it's limited to multiplayer and entirely optional.

Call of Duty: Modern Warfare is scheduled to be available on all platforms on October 25th. The beta tests will take place in September, though, with the following schedule confirmed a while ago by Infinity Ward.