Wither!
Note: Minify the command to avoid issues :)
Become Venom in only 1/2 commands!!!
HOW TO MAKE YOUR PLANTS GROW IN 3 SECONDS (2 SECONDS)
Creeper Firework
Fish Warrior Mini boss battle (1.8,1.9)
Pet ENDER DRAGON!!!!!
Wither Storm Boss in ONE COMMAND
HEROBRINE COMMAND
HEROBRINE BOSS BATTLE (See YouTube for details)