Ultra Burst

Ultra Burst (Japanese: ウルトラバースト Ultra Burst) is a transformation affecting that was introduced in. Pokémon that have undergone Ultra Burst are distinguished by the word "Ultra" in front of their species name. So far, the only known Pokémon to have this transformation is. Ultra Burst is similar to both Mega Evolution and Primal Reversion, but instead of using the energy of people and Pokémon or the power of nature, Ultra Burst uses the light of another Pokémon.

In battle
In order to undergo Ultra Burst, Necrozma needs to be in either its or  forms and be holding an Ultranecrozium Z. Once these conditions are met, the player must select a specific icon in order to activate the transformation. Once one turn has passed, Necrozma may use the exclusive Z-Move, provided it knows the move.

Ultra Burst may only be activated once per battle; any other Necrozma in the user's party will not be able to become Ultra Necrozma even if it is also holding an Ultranecrozium Z. Necrozma will revert to its original form if it faints in battle and cannot activate Ultra Burst even if it is revived.