Note: Minify the command to avoid issues :)
Weak Creeper
More Mobs: Air Zombies 1.8.7 (Read The comments
More mobs in 1 command (Read The comments!)
The helmet of MADNESS
Pet ENDER DRAGON!!!!!
Wither Storm Boss in ONE COMMAND
HEROBRINE COMMAND
HEROBRINE BOSS BATTLE (See YouTube for details)