Transfer Pak

The Transfer Pak is an accessory for the Nintendo 64. It plugs into the slot of the Nintendo 64 Controller and has a slot for Game Boy and Game Boy Color games to be inserted. This device allows for data to be exchanged from certain Nintendo 64 games to Game Boy or Game Boy Color games or vice versa. The Transfer Pak can be considered the predecessor of the Nintendo GameCube–Game Boy Advance Link Cable.

A few Mario games to use the Transfer Pak include Mario Golf for the Nintendo 64 with Mario Golf for the Game Boy Color, Mario Tennis for the Nintendo 64 with Mario Tennis for Game Boy Color, and Mario Artist: Paint Studio with the Japanese Game Boy Camera. The Transfer Pak allows for specific characters to be unlocked in Mario Golf and Mario Tennis while Mario Artist: Paint Studio allows saved snapshots to be imported or use the camera directly to take new snapshots.

Trivia

 * Mario Artist: Paint Studio is the only Nintendo 64DD game to use the Transfer Pak; by using the Game Boy Camera.