Easy it's just a Ghast Riding a GIANT
Note: Minify the command to avoid issues :)
Notch Book Troll
Diginer's Axe
Annoying Villager Murderer
Troll Potion (Troll ur m8s)
Pet ENDER DRAGON!!!!!
Wither Storm Boss in ONE COMMAND
HEROBRINE COMMAND
HEROBRINE BOSS BATTLE (See YouTube for details)