POKEMON GEN 6 ANNOUNCED

[Zadaben]

This is nowhere near as drastic a change as Magikarp turning into Gyrados. Dewott into Samurott is also a pretty big change, as is Shelmet into Accelgor. I don't think there's any argument that Pokemon don't need to look similar to their evolutions.

This looks about as authentic as it can get, as far as I can tell. If someone faked this then they 1) are one hell of a Pokemon designer and should be hired by Game Freak (or Creatures Inc. or whoever designs Pokemon), and 2) went to unusual lengths to print it out, put it on a stack of other papers, and take an amateur photo of it (or make it look like that).
Not saying it can't be a fake of course, I just think it's more likely to be real than not.

First to second evos are usually the biggest shift aside from some of the bugs/Tyranitar, Magikarp to Gyarados is based off a myth, and Shelmet to Accelgor is because of the tradeoff with Karrablast.
Also it's just not a logical advance in my opinion, in no previous stage is there any reference to any gems of any kind. The same goes for its sudden growth spurt and weight loss.