Note: Minify the command to avoid issues :)
Flying Chicken (literaly)
Ender Skeleton Boss
Death Wither Banner in minecraft
Cool Blocks like nether portal block,still water,mini TNT and more =) (not tested)
Pet ENDER DRAGON!!!!!
Wither Storm Boss in ONE COMMAND
HEROBRINE COMMAND
HEROBRINE BOSS BATTLE (See YouTube for details)