Nintendo announced yesterday that they’re once again making Hoopa available for X,Y, Omega Ruby, and Alpha Sapphire via a special code! This might be your only chance to get Hoopa, since it’s not available in-game.
The deal is valid until October 9th, so if I were you, I’d get on it right this moment. To redeem, boot up your copy of any of the above 4 versions of Pokémon, select “Mystery Gift”, followed by “Receive Gift”, “Get With Code” and then enter:
Once you receive your Pokémon via the code, enter the game. Hoopa will be available to place in your party or your PC once you speak to the delivery girl in any Pokémon Center; just be sure you have an empty slot in your party before doing so! And don’t forget to save your game.
This version of Hoopa is level 50, and comes with the special ability “Magician”. Its moveset includes Hyperspace Hole (a move unique to Hoopa alone), Psychic, Astonish, and Nasty Plot.