The the release of the Pokémon TCG: XY Ancient Origins set, the Nintendo Network is celebrating with a Shiny Rayquaza giveaway from August 12 until September 14, 2015. You can snag Rayquaza via in-game distribution for Pokemon: Omega Ruby and Alpha Sapphire during that time period. Rayquaza can Mega Evolve without a Mega Stone, and comes with Dragon Ascent.