Pokémon : S21 | E15 – Fighting Back The Tears!

After a day of shopping, Team Rocket encounters Mareanie's first love and mentor, a Mareanie that still has feelings for its former protégé. Filled with jealousy, it evolves into a Toxapex and poisons James! In his poisoned stupor, James decides Mareanie should be with Toxapex instead of with him. When Mareanie overhears this, its sadness causes it to run away. But Toxapex can't bear to see Mareanie cry, and it challenges James to a duel to win Mareanie back. After what turns out to be an underwhelming battle, James is victorious, and Mareanie joyously reunites with him! (Source: Wikipedia)