Given the task definition and input, reply with output. In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.

When the player spots a Poke ́ mon or a trainer , the battle screen appears .

Whenever the player encounters a wild Poke ́ mon or is challenged by a trainer to a battle , the screen switches to a turn-based battle screen where the Poke ́ mon fight .