To help celebrate Pokemon’s 20th anniversary, a second Mythical Pokémon is joining the party: Celebi. Originally distributed to Pokémon Gold and Pokémon Silver for the Game Boy Color, he is now available once again for a limited time via Nintendo Network. If you play Pokémon Omega Ruby/Alpha Sapphire or Pokémon X/Y, you can receive Celebi and add this Psychic- and Grass-type Mythical Pokémon to your party. Celebi is Lv. 100, and knows the moves Confusion, Recover, Heal Bell, and Safeguard. It also comes with the Ability Natural Cure.
You can download the Pokemon now just by going to Mystery Gift. It will be available until March 24th. You can get exact directions on how to download your new Pokemon here.