Wild Pokémon
Wild Pokémon (Japanese: 野性ポケモン Yasei Pokémon) are any Pokémon that have not been caught by a Pokémon trainer. They are encountered by walking in tall grass or caves, traveling with Surf, breaking open rocks with Rock Smash, or by fishing.
Wild Pokémon can be caught using a Poké Ball.
Generation IV
File:Double-battleDPHF.png
Eterna Forest's Wild Double Battle
In Pokemon Diamond and Pearl, wild double battles were introduced. There are five instances that this can happen.
The protaginist will encounter another character that needs help getting through the said location. When the trainer encounters a pokemon with this person, it will be a wild double battle.