Better to call it a demon:
Wither skeleton with an elytra, sheild and sword
Note: Minify the command to avoid issues :)
instant death poition
Death's sycth
GIANT JOCKEY! (Giant riding Ghast)
heaven's gift
Pet ENDER DRAGON!!!!!
Wither Storm Boss in ONE COMMAND
HEROBRINE COMMAND
HEROBRINE BOSS BATTLE (See YouTube for details)