MoonMillenniummon

Moon=Millenniummon is an Evil God Digimon whose name and design are derived from "Moon-Millenniummon". It is a soul Digimon that exists within Millenniummon's inner world. As a result of Millenniummon's dark spirit becoming a Digimon, it does not possess a fixed form, and although it often takes the shape of a crystal, it seems that the hatred and anger it feels against those who oppose it cause it to change shape. As it is a soul and does not have substance, it is immune to physical attacks. Even though its physical form, Millenniummon, must have been defeated first, there probably aren't any Digimon that could defeat Moon=Millenniummon; even if Millenniummon is somehow defeated, it is said that Moon=Millenniummon will separate from its now-dead physical form and be revived throughout time and space.

In Ultima, Moon-Millenniummon is.

Attacks
 * Death Crystal: Performs an incorporeal attack that is said to chop up the opposing Digimon's spirit.
 * Dimension Destroyer