@WhiteWolfBlueEyeGaming

I did some research. 'The Watcher' is actually a boss mob that spawns in the nether. It has over 3,000 health and shoots fireballs at you. Its similar to a ghast but its much more powerful and has a lot more health. It is spawned by using 'The Call Of The Watcher'. I hope this helped anyone who's reading this. Like this comment if it helped! ;)