>>13772717>Grow shoulder pads and mutate his foot>Logical stepMewtwo was originally supposed to be a Mew clone, are you forgetting that? Mewtwo Y is what Mewtwo would have been if they had succeeded - basically, Mew's Final Form.
Mewtwo X is a failed attempt at cloning Mew. Heavily mutated and built specifically to fight.
Mewtwo Y is a succcessful attempt at cloning Mew. They amplified his powers while keeping it Mew-like.
Regular R/B/Y Mewtwo is the first crude attempt, hitting neither target. It worked, but just kind of. And now with advanced gene splicing available in todays technology they're able to modify his genome.