Note: Minify the command to avoid issues :)
Omega Potion
Summon The Wither Without Building It
OP Chestplate (you can fly a.k.a glide with this thing)
Summon The EnderDragon
Pet ENDER DRAGON!!!!!
Wither Storm Boss in ONE COMMAND
HEROBRINE COMMAND
HEROBRINE BOSS BATTLE (See YouTube for details)