Stat changes upon Mega Evolving:
Attack: + 45
Special Attack: - 25
Defense: + 5
Special Defense: + 5
Ability: Grindstone- The user sharpens its claws on tougher opponents. The higher the enemy's defense, the more damage the user inflicts.
Mega Evolve from Sandslash when holding Sandslanite.
With the recent reveal of Mega pokemon, I couldn't resist trying my hand at one of my favorites. I'm not quite sure the details involved as to what changes stat-wise when a certain pokemon mega-evolves, but I imagine that Sandslash would shed a bit of his Defense to boost his Speed and Attack. Once we learn a bit more about these forms, I'll update Mega Sandslash's info.
EDIT 11/2/13: Now that the game has been out for close to a month now, we have a general idea of how the Mega forms work stat-wise. I did my best to divvy up the stat boosts to fit the average total 100 that most of the Mega forms get, plus to fit what I assume would be a straight-up melee fighter. Plus I liked the idea of an ability that totally messes over the competitive types who spam wall pokemon. : p
Micron pens, Crayola color pencils, touch-ups in GIMP.