1. Trip’s Snivy
Among Ash’s opponents, Trip is the most annoying.
In fact, Pikachu lost to Snivy due to injury after the battle with Zekrom when Pikachu lost his electric energy.
2. Gary’s Umbreon
Gary Oak is Ash’s first and most notable opponent in the entire movie.
Eevee was too fast and strong, so Ash and Pikachu lost this battle.
3. Krokorok sunglasses
Sunglasses Sandile first appeared in the episode `A Sandile Gusher of Change` in Black & White.
Sandile even evolved into Krokorok during a battle with Pikachu.
4. Leon’s Charizard
After Ash successfully conquered the championship in Alola, he continued to turn his attention to another fierce opponent, Leon.
Ash and Leon fought each other in episode 13, during which Leon and Charizard taught Ash and Pikachu about the Gigantamax mechanism.
5. Team Rocket’s Meowth
Team Rocket’s trio are familiar fixtures in the Pokémon anime world, only absent from a few episodes.
Because both sides are in a confrontational position, Meowth and Pikachu become `natural` enemies.
6. Jessie’s Mimikyu
No Pokémon from Team Rocket hates Pikachu more than Mimikyu.
Jessie caught a Mimikyu and although it never helped Team Rocket catch Pikachu, it still made Ash and Pikachu somewhat panicked.
