Pokémon: The Series Rewrite:Indigo League Part 1

Episode 12: Electric Shock Showdown

Ash and the group arrive in Vermillion City to find that the gym leader Lt. Surge wipes out every trainer's team. Ash decides to challenge him with him only Pikachu and Pidgey with Pidgey evolving into Pidgetto but it fails leading to Pikachu getting hospitalized by Surge's Raichu. Ash is told he should evolve Pikachu but it refuses and they team up and defeat Surge as Ash gets his third gym badge.