Kinda leaning towards the idea of Necrozma possessing Solgaleo and Lunala instead of fusing with them. I think Necrozma's true form is that starlight creature that's shown on the boxart, so I'm wondering if like it sheds the black crystalline armor and reveals it's true form, while simultaneously putting that armor onto Solgaleo and Lunala to gain control of them. If you look closely at the starlight creature's eyes, the color pattern in the eyes resemble the colored triangle symbol that is on Solgaleo and Lunala's head, as well as the Japanese game logos.
