Mega Muths are more powerful versions of the fearsome Muths encountered only in Castle Bleck Inner Sanctum of Chapter 8-4. Possessing a massive 200 HP, Mega Muths are one of the strongest enemies in the entire game. Since only Mario is around at the time during Chapter 8-4 and Bowser was out of the party, it's highly recommended to use the Flip ability to go by them. Especially since Mega Muths are found by other Mega Muths and other enemies as well. If one does want to fight a Mega Muth for points, then safely using Boomer from a distance is the best strategy.