>>56304859Well, in Pocket Monsters, Red's Clefairy absorbs Mewtwo's DNA and transforms into Mewthree, also a scientist in the anime or movie(I forgot which) mentions about getting started on working on a Mewthree, so maybe..
Also, it could be that Arceus created Mew as the first Pokémon and Mew created Clefairy as one of first offspring, I mean they're all from Space and the Universe existed way before Earth, so maybe the Space Pokémon came first and started later on inhabiting Earth with Clefairy being one of the first Space Pokémon to come to Earth which will also explain why Space Pokémon are still being discovered in different regions as some are ancient aliens and some are new "invaders"(Like the interdimensional Ultra Beasts)?
But that's just a theory, a Pokémon theory.