In Pokemon Gold, Silver and Crystal (and later in Pokemon HeartGold and SoulSilver),
there is a location called the Trainer House.
The Trainer House allows you to battle the trainer in it once a day.
The trainer will normally be the trainer that you last used Mystery Gift with,
however if you never used that feature before, the trainer you get to battle is Cal.
Carrie is a young trainer that frequently visits Goldenrod Department Store,
and when encountered in Pokemon Stadium 2, she can use the Mystery Gift feature with the player,
and will appear in the Trainer House in Viridian for the player to challenge.
This page holds the 3 teams that she can use.