A Corsola Caper! (Japanese: サニーゴでアミーゴ！おうがんとうのたいけつ！！ Corsola the Amigo! Yellow Rock Island Showdown!!) is the 4th episode of Pokémon: Master Quest.
Just as Ash and friends arrive at a new island, their ears are met with cries for help. A family had built their house upon a Corsola nesting ground, and when a new, hyperactive Corsola arrived and frightened off the previous Corsola residents, the ground beneath the house weakened and the house was washed out to sea. The father and daughter who had been outside during the catastrophe now look on helplessly as another daughter—trapped inside the house—is washed out toward a large whirlpool. Ash and Misty call their Pokémon to action and manage to save the young girl, but this proves to be only the first challenge of the day. As Ash and friends set about recollecting the Corsola that had reinforced the foundation of this family's home, Team Rocket soon arrives and attempts to steal not only the needed Corsola, but also collections of local artwork made from Corsola horns, which these Pokémon shed regularly. While assisting this local family, Misty waits not so patiently for an opportunity to catch the Corsola that had first driven the others away, and make it her own.
The heroes come to the Yellow Rock Isle. They soon see that the rocks are indeed yellow, as well as the streets. Misty see some pretty objects. The merchant tells her they are Corsola parts; pieces of horns that Corsola shed. Misty promises to get a Corsola. The merchant compliments Pikachu, since he is yellow. Psyduck comes out, so the merchant compliments him as well. Suddenly, Psyduck walks away, so the heroes follow him. They are led to a beach. Suddenly, Psyduck behaves upset and soon, a floating house appears. The heroes are impressed to see a one, but a girl on the house with a Corsola yells for their help.
The heroes use a boat to get to the house. However, a whirlpool beings to pull the house, so Ash sends Bulbasaur and Chikorita to use Vine Whip. Not long after, the house is at the beach, while the girl and Corsola are saved. The girl's father and sister thank the heroes for rescuing Mika, the girl. The sister asks if she can repay them. Brock begins to flirt with her, but gets interrupted by Misty. Mika's sister explains that homes, including their own, are built on Corsola nests. Her father collects the Corsola horns, which the Corsola shed. This Corsola appeared out of nowhere and it was much energetic than the others. This caused the other Corsola to leave the nest, causing the house to crash and float in the sea. Misty concludes that Corsola is a wild one. She goes to move in, but Brock pulls her ear and responds she should move out. At any case, the heroes decide to help get the Corsola back.
Team Rocket sneak into a shop, though Jessie and Meowth shush James after he fell. They find many objects made from Corsola horns. With a crown, Jessie admires herself and realizes she should live in a life full of luxury. James and Meowth remind her to put the jewelry. Jessie does that, but the merchant comes in and detects them, so Team Rocket escape. The heroes encounter them, while the father detects Jessie's crown, as he made it personally. Corsola tackles Jessie, who insults Corsola. James sends Victreebel (who gnaws on him), while Misty sends Staryu, Ash his Totodile and Jessie her Arbok. Victreebel gets tackled away, while Totodile goes to get Arbok's tail. Failing that, he headbutts Arbok. Victreebel uses Razor Leaf, but Staryu dodges and knocks it away using Rapid Spin. Using Water Gun, Staryu and Totodile part Team Rocket away from jewelry, while also blasting them off.
After retrieving the jewelery, the merchant is asked if he saw any Corsola. Since he did not, the heroes, Mika, her sister, Andrea, and their father decide to search for Corsola, who all have names, since they are part of the family. After a quick search, they find Annie, one of the Corsola. Misty decides to capture the wild one, but gets pulled by Brock, who reminds her to find the other Corsola. Later, the heroes try to find the others, though Misty sees it is quite difficult. Suddenly, Bonnie appears and joins with Mika. They come back to a place where Brock left some Pokémon food to lure them in. They spot two Corsola, who eat. The wild Corsola cheers, causing them to get frightened, but Ash and Andrea get them before they run off. Team Rocket notice they are gathering Corsola. Meowth knows if they were going to bring these Corsola to the boss, he'd celebrate fortheir success. James goes to capture them, but Jessie has a better idea in her mind.
Noctowl scouted and found two more Corsola, Donnie and Ronnie. With all Corsola back, Misty goes to capture the wild one. However, Team Rocket capture the Corsola using cables, but Misty deflects the one intended for the wild one. Team Rocket take them away, thankful that the twerps got them back. Ash sends Noctowl, while James sends Weezing, who uses Smokescreen to stop it. Jessie is pleased that, with Corsola, she can get a lot of jewerly to make her famous. Noctowl comes out of the smoke and pierces their balloon. Team Rocket fall down,w hile the heroes track them down. Jessie still wishes the Corsola to be her subjects as she is their Queen, but gets tackled by the wild Corsola. Misty sends Staryu, who uses Rapid Spin to cut the cables. Jessie sends Arbok and James Victreebel, the latter chewing him. Corsola tackle Arbok, so Victreebel uses Razor Leaf. Corsola dodge and tackle Arbok, who wrapped Staryu. Victreebel uses Vine Whip on the wild Corsola, tossing it and defeating it.
Due to Recover, Corsola is once more ready to battle. All Corsola use Spike Cannon, causing Team Rocket to retreat to the balloon. They hit a machine, which explodes, blowing Team Rocket away. After the battle, Misty faces the wild Corsola, determined to capture it, since she needs it to become a Water Pokémon Master. Misty sends Poliwhirl to battle it. Poliwhirl uses Bubble on Corsola, who retaliates by tackling Poliwhirl. Poliwhirl uses Double Slap, defeating Corsola, but it recovers. Poliwhirl uses Water Gun, but Corsola's Mirror Coat deflects the attack back. Polwhirl uses Bubble, so Corsola retaliates by tackling. Poiwhirl uses Double Slap, followed by Tackle. Corsola is defeated, so Misty uses Lure Ball to capture it, and succeeds.
The heroes wave hands as they bid goodbye to Andrea, Mika and their father, then continue their journey though the Whirl Islands.
- Like the Dwarves of "The Hobbit," each pair of Corsola had names that rhyme.
- The "Who's that Pokémon?" is Electabuzz.
When Bayleef and Bulbasaur were pulling the house, Bayleef is colored like Chikorita.