Mewtwo and Mew, in the looks they had back at the day of Pokemon Blue/Red, comment on their respective appearances.

The second version of Pokemon 1, Blue/Red change the appearance of many Pokemon compared to the original version, Pokemon Green.

While Mew looked like a mini-Mewtwo back in Green, she now looks closer to her modern look, although her feet are very tiny and her tail is relatively short.

It's the opposite for Mewtwo. While his Green self is close to his modern look, his Red/Blue one really looks like an evil ape with a stupidly long and thick tail.

Roles inverted, thus...