Wither

The Wither is a three-headed Hostile Mob Boss that will be added in Update 0.16.0.

Spawning
The Wither can be spawned by placing four Blocks of Soul Sand in a T-shape and placing three Wither Skeleton Skulls on top. The last block placed must be one of the three Wither Skeleton Skulls.

Behavior
Once the Wither is spawned, it will remain dormant for a few seconds, then release a powerful explosion that can destroy Obsidian. The Wither shoots "Wither Skulls" that explode and inflict the Player with the Wither Status Effect. They also cause large explosions when contact is made on the Player, and any Block surface. If the Wither gets under half Health, it will release an explosion and spawn 3-4 Wither Skeletons. During this state, it will not take damage from Arrows and sometimes does a charge attack directly to the player, destroying terrain in its path and making it more versatile.

If the Wither is calm, it simply hovers and is unable to jump.

Wither Skull
There are two types of Wither Skulls: a fast moving black one and a slow moving blue one. The black Wither Skull cannot destroy blocks with a Blast Resistance above 20, like a Ghast's Fire Charge. They are also the same speed. The blue Wither Skull has the same explosion strength as the black Wither skull and move much slower, but it can destroy all blocks (except Bedrock, Invisible Bedrock and End Portal Frame), making it much more destructive to the terrain. The only way to escape the blue Wither Skull is to either dodge or deflect it back at the Wither, much like Ghasts' fireballs.

Trivia

 * The Wither cannot be spawned, it must be assembled, like Iron Golems and Snow Golems.
 * However, it can be spawned with a spawn egg that is only obtainable through Commands.
 * Like Iron Golems, the Wither must be assembled in a "T" formation.
 * Like other undead Mobs, the Wither is harmed by Potion of Healing and healed by Potion of Harming.
 * It will be the first boss added to Minecraft Pocket Edition.
 * It will also be the only Hostile Mob that must be Crafted by the player.
 * The Wither appears on four side of Chiseled Red Sandstone.
 * Version Exclusive: Spawns Wither Skeletons when it reaches 50% health.
 * It will attack all mobs except for undead Mobs.