The Gamecube version of Harry Potter and the Prisoner of Azkaban (2004) and be linked with the Gameboy Advance in two ways.
First, by connecting an empty GBA, 2 mini game games can be downloaded: a Bewjeweled clone and a Mode-7 flying racer.
The other linking feature requires the GBA cartridge version of Harry Potter and the Prisoner of Azkaban. Using an Owl Care Kit, the GBA is used to strengthen an owl like a virtual pet. When strong enough, it can retrieve items for in-game use. Then, it can be sent to the Gamecube game to race.