Wither floating around (Image via minecraftpocketedition.wikia.com) As mentioned earlier, Withers can only be spawned into Minecraft using soul sand and Wither Skeleton heads.

There are only a few boss mobs in vanilla Minecraft, but the Wither may be the most fierce among them, depending on the context. A boss that players can summon, the Wither isn't necessary to beat ...

A secret new Minecraft mob called the Wither Boss who floats around chucking festering, withering, exploding skulls at you, your friends and your pets. Coming to a Minecraft update near you soon.