Players of Pokémon X, Pokémon Y, Pokémon Omega Ruby or Pokémon Alpha Sapphire will be able to catch a level 50 Mythical Hoopa at GAME stores between October 23 and November 5, 2015.
Hoopa cannot be found during normal gameplay. Players visiting GAME stores will be given a unique code printed on a receipt – no purchase necessary – which can then be redeemed.
Mythical Hoopa has the Magician Ability and is recognised by its two horns and the golden ring that adorns its body. The ring allows it to bend dimensions and move objects across great distances. Hoopa’s moves include Hyperspace Hole, Psychic, Astonish and Nasty Plot. Once added to your game Hoopa can be transformed from its Confined form into the powerful Hoopa Unbound.
How to redeem you Mythical Hoopa code:
1. Select “MYSTERY GIFT” on the main menu, and then “RECEIVE GIFT”. Select “YES” to confirm.
2. Select “GET WITH CODE”, and then select “YES” to confirm.
3. Enter code.
4. Resume the game, ensure there is enough space, and speak to the delivery girl in any Pokémon Center to receive Hoopa.
5. Save the game!
Source: Pokemon Company