Boss Mobs

 The wither doesn't spawn naturally, instead the player must spawn it themselves, making a T formation out of four blocks of soul sand, with three whither skeleton skulls on top of the three top most blocks. Note: the wither doesn't have to be beaten to complete the game, all it does is drop a nether star, which allows the player to build a beacon. The wither is a undead mob, therefor it is damaged by splash potions of healing, and healed by splash potions of harming. When first spawned, the wither is immune to all attacks, until its health bar is full. Upon getting to max health, the wither explodes, showing that the player can now deal damage to it. The wither has the most health of any mob it the game (Not including the programable agent from education mode.) The wither attacks all peaceful mobs, some neutral and hostile mobs, and of course all players on survival or adventure mode. The wither launches wither skulls at the player that blow up when they come in contact with a player, mob, or block. If a player is hit, the player will get the wither effect, which does damage to the player until it runs out, the player dies, or the player drinks a bucket of milk. If a mob is killed it drops or plants a wither rose. When the wither reaches half health, the wither becomes immune to all arrows and tridents, and gets an extra armor buff. Upon killing the wither, it will drop a nether star. Bedrock Edition: Once the wither has reached full heath, and spots a target, it will move to a random location, fire three wither skulls, and one dangerous wither skull, before moving to the next location. Once the wither reaches half health, it still gets an armor buff, and is immune to arrows. But instead of going to random locations, it dashes at its target breaking all blocks (except bedrock) and damaging all mobs in the way. It still drops a nether star on bedrock edition.

The Ender Dragon

Unlike the wither, killing the ender dragon is necessary to complete the game. Upon reaching the end, there will be obsidian pillars with end crystals at the tops of them. To be able to easily defeat the ender dragon, the player must destroy these because they regenerate the dragons health. The ender dragon has two different attacks, dive at the player, and shoot them up into the sky, or shoot dragon  fireballs at the player. The fireballs explode on impact, and leave behind a lingering effect called dragons breath that does massive amounts of damage. Every once in a while the dragon will come down to the portal out of the end, and stay there for a while. During this time, the player can do damage with their sword, as arrows do no damage while the ender dragon is down here. The wings also take no damage, so the sword must hit the body of the dragon to do damage. Explosions also do damage while the dragon is at the portal. When the dragon is killed, it will drop 12,000 experience points, light the portal to get out of the end, and spawn a dragon egg in the center of the bedrock. It will also spawn another portal that is only accessible via ender pearls, that takes the player to an area where end cities spawn. To re-summon the ender dragon, the player must get four ender crystals, and place then along the middle of the edge straight lines of bedrock. All re-summoned ender dragons will only drop 500 experience points.