Variants become zombies.
Mo ‘Zombies Mod 1.7.2 and 1.7.10 is a mod that was not available for the current version over a year ago. But today we can itself increase both the quantity and the variety of zombies in Minecraft. By installing this mod will have 13 variants zombie.

Detail and Download here : Mo ‘Zombies Mod

Homepage: Mods for Minecraft