D.M.M.

The D.M.M., aka the Death Moon Monger, is a massive post-moon lord boss that is a grey circle, which, you do not fight it, but use weapons across your world in different things. It is summoned by the Tri Stone.

Attacks
Death: Your world blows up. Just kidding, it just kills you, and you have to restart from the last save.

Meteor Missiles: Very small meteors crash all over your world.

Trivia
It is a reference to the Moon from The Legend of Zelda: Majora's Mask