Boss battle only in 1.8
Note: Minify the command to avoid issues :)
Elite Rogue Trooper 1.12.2
Battle set
Winningapple's head
Skeleton Jeb Boss Battle (Don't underestimate)
Pet ENDER DRAGON!!!!!
Wither Storm Boss in ONE COMMAND
HEROBRINE COMMAND
HEROBRINE BOSS BATTLE (See YouTube for details)