Chesnaught: Half hedgehog, half blast-shield, all badass. (Benny Galkin)
And the winner of the most unexpected evolution goes to...aw, hell, you obviously know who it's going to, it's under the "Chesnaught" entry for pete's sake. Anyways, yeah, it's Chesnaught, who somehow went from a little chipmunk with a hoodie to a ball-shaped chipmunk to DWAYNE "THE ROCK" JOHNSON BUT A PLANT POKEMON SOMEHOW. I mean, look at that thing - it's basically the grass-version of Blastoise, except it has some serious arm strength too. So work hard, eat right, and stay in school kids - and one day you too may grow up to be a badass fighting-plant-mammal (that's owned by a fatherless child).
Talonflame is one of the best flying types I've ever used. Matter of fact it is the first bird pokemon I ever got to Level 100. (Colin Miller)
Talonflame is essentially the Pidgeot of Gen 6 - it starts off as a weak, early-game, low-level bird that ends up with a pretty sizable final form. But there are a few key differences between Pidgeot and Talonflame: Talonflame actually looks cool, is a fire-type, and - most importantly - doesn't have a weird rainbow combover haircut.
Haven't played this generation yet either but Pangoro looked pretty cool. (Joseph Massimo)
With most pandas on a constant verge of extinction, Pangoro stands apart as a strong, battle-ready panda that has some kind of cool overcoat made of its fur. Really, it's the only panda in recent memory of anything that looked remotely threatening, which is unfortunate because - c'mon - they're BEARS (technically racoons or something, I know, but go with it). If all pandas were like Pangoro, they would definitely not be in any danger of going extinct (also because I'm pretty sure it's impossible for most Pokemon to actually die, so they got that going for them).