Hey guys! I made a one command block creation, called the Nature Guardian Boss Battle in only one command block! The module adds a boss with six different abilities, three battle phases, six custom drops and a random island generator that the boss spawns on!

Download:
Copy the command from the download and paste it into a command block.

Video:


Battle:
First, you must place a sunflower and then use bonemeal on it 32 times. This will then cause the island to begin generation. Your screen will go black and you will have to wait about 30 seconds for the island to generate. Once generated, you will need to climb the vines and upon reaching the top, the boss will spawn. He will start off in a state of invincibility and he will not move or attack you. This will give you time to prepare for battle.
In his second phase, he will attack you. However, he will still be invincible to all regular damage. To hurt the boss, you will need to make him stand in any kind of long grass or flower. He will use all six of his abilities in this phase.
1. He will give the player a a wither effect when damaged.
2. Perform a mega jump
3. Summon insects that will break any nearby grass and flowers
4. Teleport to the player
5. Slow the player and prevent them from jumping
6. teleport the player down a block
In his third phase, he will be able to take damage from a sword and you must kill him. He will emit particles when in this phase, so it is obvious when he is killable.

Items:
The boss has a 50% chance of dropping each item. There is an armor set, the mage robes and two items, the Flower Power and the Growth. The Flower Power is a weapon that does 8 attack damage and has no durability. The growth egg when placed will make everything in the world act as if it had bonemeal used on it.
The Mage Robes will only provide their buffs when the whole set is on. The set will give you a speed and jump boost two constantly. It will also make the Growth egg infinite, so when you use it it will not consume the item. The set will provide you with a reasonably strong regeneration effect when standing in grass, flowers or vines. It will also give all nearby entities slowness and weakness. Finally, you can also use the set to pull items from afar to yourself. 

Installation:
1. Obtain a command block. Use /give @p command_block
2. Place the command block and paste in the command from pastebin: pastebin.com/huSj5KnV
3. Power the command block with a redstone block and if you did it correctly, a structure should spawn.