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The Pokémon Colosseum Bonus Disc was only available by reserving a copy of Pokémon Colosseum. Its contents vary depending on region, but in all cases contain previews of various games or movies and one or more special downloadable Pokémon.
US Bonus Disc
cover art for the US bonus disc
This disc contains previews of Pokémon Colosseum and the movie Jirachi: Wish Maker, as well as a downloadable Jirachi. To receive Jirachi, a Nintendo GameCube–Game Boy Advance cable, an English copy of either Pokémon Ruby or Pokémon Sapphire, and an empty spot in the party is required. With everything connected properly, Jirachi will appear and be transferred to Ruby or Sapphire. The process of obtaining Jirachi can be repeated as long as the save file that is receiving Jirachi has not already used this disc. If the game that is being used to get Jirachi has the Berry glitch, it will be fixed upon receiving Jirachi. It is not required to own Pokémon Colosseum to receive Jirachi.
Japanese Bonus Disc
cover art for the JP bonus disc
This disc contains a Celebi and previews of Pokémon Box Ruby & Sapphire, Donkey Konga, Mario & Luigi: Superstar Saga, Donkey Kong Country, F-Zero: Maximum Velocity, Mario Kart: Double Dash!!, and Mario Party 5.
Unlike the US Bonus Disc, owning (a Japanese version of) Pokémon Colosseum is required at first to receive Celebi. The Colosseum save file must have all 48 Shadow Pokémon purified. After Celebi has been transferred to the Colosseum save file, the Bonus Disc can then be used to transfer up to 48 more Celebi to any Japanese Game Boy Advance Pokémon games as long as the player has beaten the Elite Four and saved in a Pokémon Center. A Pikachu is also available from this disk.