Pokemon getting new forms within a generation that cannot be accessed or used in any way in other games of that generation, which also means you can't fight using those fuckers. Giratina, Kyurem, and Rotom are just a few offenders. Oh, and they have the gall to pull it with event Pokemon that weren't even released yet (Deoxys, Shaymin, etc). Why the fuck don't they come up with all of these extra forms in advance and leave that shit behind on the first games but just inaccessible without future games? Fuck, at least they had the decency to leave behind Mega Lati@s, but I'm not going to be surprised when Zygarde and Volcanion end up with some new form bullshit down the road that we can't get in X and Y.