Gaster's shaking Mettaton's hand with the one that doesn't have a gaping hole in the palm--yes, it seems this younger one has one whole hand left.

"Star? Of what? Or. I'm not sure how much I should be asking about what will happen. It may not, there are too many timelines."

He's already wondering about Flower-Asriel. Will that happen someday for himself and his son? How does a long-dead monster become a flower??