Alpha Zombie

Alpha Zombie is a Halo 3 Infection game type variant. In this variation and game type, the players who start the match as a zombie are more powerful than those they kill and infect. The Alpha Zombie has Active Camo, can run faster and can jump higher than the normal zombie. You can also change the attributes of the Alpha Zombie and the regular infected Zombies in the edit gametype section of the Custom Games pregame lobby. You can also increase the points that a player can receive when they kill the Alpha Zombie, or even make the Alpha zombie weaker than the zombies infected. The Alpha Zombie also refers to the starting zombie of each round whether or not the Alpha Zombie gametype is selected.

Trivia
There is a game type in halo 3 that is called 'fat kid' the alpha zombie is impossble to kill but if you can assn. the zombie you kill it.