While you may think that science and malleable metal alloys comprise the majority of what makes a Spartan so special, the reality is that even John-117 himself is little more than a crunchy cool ranch husk filled with carbonated green stuff. Spartans are made of Doritos and Mountain Dew, is what we're saying – that's why the PR partnership between Halo 4 and PepsiCo seems like such a no-brainer.Potential players can get a head start on accruing extra experience by registering an account over at dewxp.com or doritosxp.com. Select codes from Mountain Dew and Doritos packages – starting on October 15 – can be used to increase your XP in Halo. There are also goodies up for grabs, including consoles and controllers, Warthog toys and free Xbox Live subscriptions, among many other prizes.