This image is made by Masaaki Iwane (one of Pokemon Anime's animators)

Just noticed a cracked black crystal (above Buzzwole) in this image.
Could it be Necrozma?

I think Necrozma will get more forms than one:
-Star Form (Similar to Cosmog)
-Cocoon Form (Black Cracked Crystal, Similar to Cosmoe)
-incomplete Form (We've seen)
-Complete Form (Powerful than Solgaleo and Lunala)