This map lets you in a very easy way see what it like to fight the Wither Boss. It will only work for the latest 0.16.0 beta which is currently only available for Android. But once it's out for the other operating systems too it will work for those too (e.g. iOS and Windows 10) too. Everything is set up in a way where you just need to place an item to spawn the boss.
Creator: Y3Gamer, Twitter Account
How to fight the Wither Boss?
Begin by taking one wither skeleton skull from the item frame in the lobby. Then look in the chests and take whatever gear and weapons you can find.
Once you feel ready to enter the wither boss arena by stepping on the pressure plate and enter through the door access. In the center of the room you will find a small structure.
Place the wither skeleton skull on the two soul sand blocks in the middle and then wait for the Wither Boss to spawn.
Once you've defeated the wither boss it will drop a Nether Star.
Important: Install this mod as a texture/resource pack. It requires the 0.16.0 beta (click for beta sign up) or above.