One Trick Phony! (Japanese: バトルパーク！ＶＳカメックス・リザードン・フシギバナ！ Battle Park! VS Blastoise, Charizard, and Venusaur!) is the 39th episode of Pokémon: Master Quest.
Ash battles a trainer and her Smoochum while on the way to Blackthorn City, but just as Ash was about to finish it, she calls off the battle saying it's too exhausting. However she does tell them about a new Battle Park where Ash can battle to his hearts content. Little did he, Misty and Brock know that Team Rocket infiltrated the battle park so they can steal the park's Pokémon. When Ash gets there he signs up for a battle and soon three trainers appear. Who are these three trainers and what Pokémon do they have to battle Ash with?
Ash's Pikachu battles with a trainer's Smoochum, as a training before Blackthorn City. Smoochum, nicknamed Josephine, uses Sweet Kiss, but Pikachu dodges. Josephine does so once more, but in the last moment, Pikachu uses Agility to dodge and counters with Quick Attack. Pikachu uses Thunderbolt, but the trainer cancels the match. She admits she is too exhausted. Ash wants a battle, so the trainer advises him to go to Battle Park, a location where trainers can challenge any Pokémon to a battle. Ash goes there, while Brock hopes to meet pretty girls.
At the park, Team Rocket cleans the Poké Balls. The owner comes and gives them more Poké Balls to clean, as he needs to go shopping at the nearest town. Team Rocket is angered, as they have to do this low job. The heroes try to get someone's attention, so Meowth thinks they can use these park Pokémon to catch Pikachu. The heroes are about to go, but Jessie (disguised) welcomes them to the park, which is always opened. They come to the center, where James (also disguised) tells them they are too busy and cannot choose most of the Pokémon to battle with. Brock notices nobody else present, so James offers them mysterious Poké Balls, so they can choose to battle the strongest Pokémon the Park offers.
The heroes walk and notice many battle fields. They meet up with three trainers (who are Team Rocket) to battle with. The heroes are ready, but wonder where the judge is. Team Rocket panics, but Brock offers himself to be the judge. Ash battles James, who sends a Venusaur. Ash sends Cyndaquil to battle against it. Venusaur uses Razor Leaf and while Cyndaquil dodges, the leaves cut through trees, causing them to fall down. Team Rocket is amazed, so James orders Venusaur to tackle Cyndaquil, who gets hit. Venusaur uses Vine Whip, and while Cyndaquil dodges, the attack damages a tree. Cyndaquil fails to dodge a Vine Whip, so Venusaur uses Razor Leaf to defeat it, but Cyndaquil's Smokescreen causes it to dodge.
Cyndaquil uses Swift, knocking Venusaur down. Cyndaquil uses Flamethrower, hitting Venusaur with it. Venusaur uses Solarbeam and Cyndaquil uses Flamethrower on it. However, Venusaur is charged and fires Solarbeam, causing Cyndaquil to be defeated. Ash calls Cyndaquil back and admits this was a good battle, wishing for a next battle. As Meowth and James argue, Jessie snatches the next Poké Ball, sending a Charizard. Meowth thinks Jessie and Fire-types should not mix, though Ash sends Totodile. Jessie orders Charizard to use Poison Sting, but Charizard does not know that move. So, Totodile hits it with Water Gun, making Meowth and James annoyed. Jessie orders Charizard to dig. James and Meowth know it can't dig, but Charizard proves them wrong.
After emerging, Charizard uses Iron Tail, hitting Totodile with it. Charizard goes to use the same attack, but Totodile dodges and headbutts Charizard. Next, Totodile and Charizard use Scary Face. However, both are forced to scare the opponent too much and fall down. Totodile uses Water Gun, but Charizard flies off and uses Flamethrower. Totodile uses Water Gun to stop it, but fails and gets hurt. Charizard continues with the same move, so Totodile uses Water Gun on the ground to dodge. While in air, Totodile's Water Gun defeats Charizard. Ash is pleased, so Jessie calls Charizard back. James and Meowth argue, so Jessie takes the last Ball and orders them to get some goods while she battles. Meowth objects, but Jessie yells at them, so they comply.
Jessie sends Blastoise, so Ash sends Pikachu. Jessie reads the rule book to see what moves Blastoise can use. Depsite Jessie not being ready, Blastoise gets hit by Quick Attack. Blastoise uses Skull Bash, but Pikachu dodges. Blastoise uses Bubble, but gets hit by Quick Attack. Pikachu uses Thunderbolt, but Blastoise withdraws and takes no damage. Blastoise retaliates with Hydro Pump, hitting Pikachu with it. Blastoise keeps hitting Pikachu with Hydro Pump. However, Pikachu uses Thunderbolt, canceling the attack and hitting Blastoise with it. Blastoise gets hit by Thunder and is knocked out on Jessie, who calls it back. Jessie sends Arbok, who uses Poison Sting. Pikachu dodges, but is distracted and taken by James and Meowth. Jessie goes on the balloon, since they stole all the Pokémon from the Park.
Ash sends Totodile back, while Misty sends Politoed. Totodile's Water Gun crushes the robot arm, so Ash gets Pikachu back. Politoed uses Water Gun after some clapping, bringing Team Rocket's balloon down. However, Team Rocket still has the Poké Balls, as they send Charizard, Blastoise and Venusaur. Blastoise, Venusaur and Charizard turn on Team Rocket, as they are very loyal... inside the park. So, they use Hydro Pump, Flamethrower and Solarbeam, blasting Team Rocket for good. Misty and Brock are pleased on Ash's victory (despite Team Rocket's involvement). Ash is also pleased, as he, Brock and Misty continue onwards.
The "Who's that Pokémon?" is Tauros.