Which company developed Pokémon Colosseum for the Nintendo GameCube?

Genius Sonority developed Pokémon Colosseum for the Nintendo GameCube.

Pokémon Colosseum was published by The Pokémon Company and Nintendo, but its developer was Genius Sonority. The studio created the game as a 3D role-playing spin-off set in the desert region of Orre. It launched in Japan on November 21, 2003, followed by releases in North America and Europe.

Genius Sonority was founded by former members of Nintendo's internal development staff and became associated with several Pokémon projects. In Colosseum, the studio built a story around Wes, Team Cipher, and Shadow Pokémon. The game also included extensive double battles and connectivity with the Game Boy Advance Pokémon titles.

Game Freak is commonly mistaken for the answer because it developed the core Pokémon role-playing games, including the original Red and Green. HAL Laboratory is another plausible mix-up because it developed Pokémon Snap. Creatures, meanwhile, has been involved in Pokémon development and trading-card-related work, but it was not the developer credited for Pokémon Colosseum.