She's trying really hard to think about what it could be that Diya is talking about. It doesn't really make any sense to her. If it's not shapeshifting, what could it be? She's quiet for a moment, looking at what Diya is pointing too.

"It.. might be fusion?" Which isn't really something Lapis would have ever thought about in this place because it's not like she can. "They merge together and then fall apart?" Clearly it's not a stable fusion that's going on, but it does seem to be one none the less.

Or, that's her best guess, anyway.