download: http://www.mediafire.com/download/8su3fqsh66bly3q/Wither Storm boss fight.zip
The wither storm is from MInecraft Story Mode, if you don't know what that is, it's a action game made by Tell Tale Games and you make the choices.
download minecraft story mode: https://www.telltalegames.com/minecraftstorymode
The command for it is by THcommandblocker. Thank you for making it bro:D Check his channel out: https://www.youtube.com/user/THCommandBlocker