VERY WEAK!
Note: Minify the command to avoid issues :)
Mobs with special abilites! only ONE command! 1.8.7 (Read The comments! )
You will cry.
Evil Golems in 1 command
Red bull 2.0 (Aka Black red bull)
Pet ENDER DRAGON!!!!!
Wither Storm Boss in ONE COMMAND
HEROBRINE COMMAND
HEROBRINE BOSS BATTLE (See YouTube for details)