|Mega Rayquaza is a beast. Seeing as|
every new game has at least one
super-powerful pokémon, I shudder
to think what could out beast this thing in
the next set of games...
This Rayquaza is likely a tie in to the the previously released Ancient Origins card set, as the set has a shiny Mega Rayquaza EX card. Oddly enough, there is no Shiny Rayquaza EX so by Mega evolving you are essentially turning a regular Rayquaza into a shiny. Same goes for the Shiny Primal Groudon and Kyogre EXs from the set. It doesn't really matter so much, it's just a funny circumstance.
For those of you without Omega Ruby or Alpha Sapphire, only X and Y, I will be downloading a few extra in my Alpha Sapphire. I've never actually started a file on it, so I just use it to get events. I download the event, get my pokédex, dump the event on Bank, reset, and download again until I get tired of it. If you happen to have a spare of a different event, I'll gladly get you a Shiny Rayquaza, teach it something to get rid of Dragon Ascent, and trade it to you. I'm a nice guy like that.