S2·E11 Bye Bye Psyduck

Episode recap

While stopping on another island to rest, Misty notices that her Psyduck's tail is glowing. A nearby trainer observes the glowing tail and suggests that it may mean it is time for the Psyduck to evolve. Intrigued by the possibility, Misty decides to challenge the trainer to a battle. When Misty discovers that her opponent possesses a Golduck, she uses it to her advantage and easily defeats the trainer. However, Team Rocket has other plans during this time. Later, the situation takes an unexpected turn when the Golduck turns out to be a wild Pokemon, and Misty's original Psyduck reappears.