Pokémon Sun and Moon - Celesteela concept art

I think that based on this pokemon japanase name it refers to the Kaguya myth in few words, it's a beutiful woman from the Moon in the Earth, found by cutting bambo, Moon people come get her back with a space ship years latter, Emperor of japan doesn't want to and wants to trap her and she delivers punishment with assistance with her rage making mt fuji a volcano that erupts.

It makes a lot of sense since it's a rocket, steel flying type, can use fire and grass attacks despite its type and it's a beautiful cinnamon roll.

That story is also a prove that alien had visit Earth in the past.