Evolution/Side games/Hey You, Pikachu!

Some missions in Hey You, Pikachu! involve interacting with other Pokémon in certain ways to cause their evolution. In Caring for , the player and Pikachu supervise a group of Caterpie, who will evolve into and then  if treated well. In Field Trip, Pikachu can water wild and, causing them to evolve into Gloom and , respectively.