A Pokémon is recognized as an outsider if its recorded data about its Original Trainer does not match that of the player for the current game. The exact properties checked vary between different parts of the game.
When used in a battle, outsider Pokémon may disobey the player if the player does not have the appropriate Gym Badges or island challenge Stamps. A disobedient Pokémon may use a different move, do nothing, hurt itself, or even take a nap (putting itself to sleep).
Outsider Pokémon also grow faster than native Pokémon. Outsider Pokémon gain 1.5 times the normal experience points for participating in battles. From Generation V onward, if the outsider Pokémon is from a game in a different language, it will gain 1.7 times the normal experience instead.
Outsider Pokémon normally can only have a nickname set or changed by their Original Trainer. In Generation VIII only, any Pokémon that does not have a nickname and was not met in a fateful encounter can be given a nickname in a game of the same language as its language of origin, even by players other than its Original Trainer; however, once it is given a nickname this way, it has become a nicknamed Pokémon, so players other than its Original Trainer cannot change its nickname.
From Generation III onward, Outsider Pokémon have their met location listed as "apparently met".
The exact properties checked to determine if a Pokémon is an outsider vary between different parts of the game.
A Pokémon is considered an outsider Pokémon for the purposes of Name Rater if any of the following properties of the Pokémon do not match the player's.
|Game of origin||✓||✓||✓|
Experience and obedience
|Game of origin||?||?|
Methods of obtaining outsider Pokémon
Outsider Pokémon can be obtained in a number of ways. Pokémon originally obtained in another player's save file obtained in a trade are outsider Pokémon. Additionally, in-game trade Pokémon are also treated as Outsider Pokémon.
Normally, the player is treated as the Original Trainer of gift Pokémon they receive from NPCs; however, in some particular cases, such as Webster's Spearow in Gold, Silver, Crystal, HeartGold, and SoulSilver and N's Pokémon in Black 2 and White 2, the NPC is retained as the Pokémon's Original Trainer.
Pokémon obtained from event distributions usually have predefined Original Trainers, and so, they are considered outsider Pokémon. Only on rare occasions, such as Pokémon Sun and Moon's Snorlium Z Munchlax and Egg distributions, do the distributed Pokémon's Original Trainers match the player's.