“Infection is this really great gametype, inspired by a custom game devised by our community in Halo 2, which we added official support for in Halo 3. In Infection, most players start off on a Human team, with one or more players starting off as Zombies. The odds are stacked heavily against the Zombies at first, but when a Human is killed by a Zombie (as they inevitably are), they join the Zombie team and turn on their former teammates.” Good ol’ Frankie.

Source: Gamestooge