Following the lead of World of Warcraft, where players are now threatened by a zombie uprising that is connected to the launch of the Wrath of the Lich King expansion, Rockstar is saying that players in Grand Theft Auto IV should also be careful about infected individuals who display zombie-like behavior.

The in-game company Eugenics Inc posted, on the Social Club boards of the game, a warning that a “contagious disease” might become a threat. Then, the multiplayer got invaded. There are zombies, which can sometimes be identified by their yellow shorts, that will infect anyone who kills them. The problem is that there are quite a lot of infected that are not wearing the distinctive dress, so in all multiplayer modes of the game no one is safe from the outbreak. Those who get infected also get the “Let Sleeping Rockstar Lie” Achievement on the Xbox 360. Those registered with the Social Club can also access a map of the world and of the United States, tracking the spread of the outbreak in real time.

It's not clear, at this point, for how long the zombies will hang around in multiplayer, or whether Rockstar plans to develop this into a 28 Days Latter type of scenario, where players would need to work together in order to repeal the assault of the undead. Some people are also thinking about how zombies could be implemented in the single player section of the game.

Microsoft promised, ever since the videogame was launched, that GTA IV would receive exclusive downloadable content on the Xbox 360. Most people have said that the DLC will likely consist of new missions or new cities, but it might just be that players will get a chance to combat zombies. Of course, it would not suit the realism that GTA IV is trying to promote, but it would surely be fun to make a last stand with all the citizens of Liberty City.