The artist behind the tumblr blog In-Progress Pokemon sets out to show what would happen if the world's most collectible monsters went through metamorphosis like real animals instead of the fantasitical display of light and magic that happens in the games. Without that distraction you have to start thinking of those awkward in-between stages that makes puberty just so devastating, and for some creatures it takes a lot of imagination to make two disparate designs flow together. What's really neat is how they take the extra steps to make sure that even the poses from the original art lead naturally from one another.
If there's a Pokemon that you want to see get this evolutionary upgrade, the artist does take commissions. Be sure to follow the blog on tumblr to get all the updates as they come out.