Curbing the Crimson Tide! - S9.E21

There's big trouble in the big city when Ash and his friends pay a visit—a mysterious talking Pokémon in a crimson cloak known as Red Lighting has been battling all the Trainers in town, and it acts like a real supervillain when it wins! May's plans for a nice day out are ruined when Red Lightning humiliates her and her Squirtle, so now the heroes are out to uncover who or what is behind its activities.