Trust the Minecraft community to make a mod of a mod. In this case they're currently building a version of DayZ, the brilliant persistant Arma II zombie mod. The more you think about it, the more ...

Minecraft gets a zombie invasion mod! Explore new zombies like the balloon zombie and party zombie. But beware the scarf zombie—it throws snowballs & angers creepers!

This is because Mutant Zombies are only in one of the Minecraft mods. Players cannot see these mobs walking around without entering a mod. Mutant zombies are larger, stronger, more powerful versions ...

I've been playing the MineZ public beta, the DayZ inspired, server-side Minecraft mod that chucks 150 players into a zombie-infested open world and expects them all to survive and play nice together.