Casting a Paul on Barry! (Japanese: シンオウリーグ三回戦！シンジ対ジュン！！Shin'ō League Third Round! Shinji VS Jun!!) is the 184th episode of the Diamond & Pearl series, and the 650th episode of the Pokémon anime. It aired in Japan on July 15, 2010 and in the United States on December 4, 2010.
The episode starts with Paul defeating a female Trainer. Then, Ash tells his Snorlax to use Body Slam on his opponent's Grumpig, defeating it. With the second round of battles over, the battling pairs for the third round are shown. Conway will be battling Ash, and Barry will be battling Paul. Outside the stadium, Ash and his friends are looking at the screen. Then, Conway appears out of nowhere again. As Conway says something, Dawn walks back and accidentally bump into Barry. Barry scolds Dawn for making him fall, and Dawn tells him that he should not be running. The two starts to fight, but Brock stops them. Ash asks Barry what he is running for. He replies that he is looking for Paul. He runs off. Team Rocket continues to sell their merchandise but everybody passed by them. Meowth takes out the Jessilina toy and a Meowth door figure. But there is nobody listening to them. James asks why no one buys their merchandise. Jessie suggests that the Meowth figurine is not good enough, and Meowth denies that, and says that the Jessilina figurine is not nice. Both of them start to quarrel. They say that they will do their best to sell their merchandise. In the evening, Paul is checking the data of Barry, when he hears Barry's voice. Ash stares at Paul. Barry asks Paul if he is looking up on him, and he replies yes. After Paul leaves, Barry checks on Paul's data. Conway appears suddenly and tells Ash about the Darkrai and its Trainer. Then Conway goes away and Barry and Ash rush out.
The battle of Paul and Barry is about to begin. A rock field will be the battlefield for their battle. Barry and Paul appears on both side of the battlefield. Barry chooses Skarmory as his first Pokémon and Paul chooses Magmortar. Dawn checks the data of Skarmory on her Pokédex. Barry starts the battle with Spikes. Paul tells Magmortar to use Flamethrower, the strong attack takes out Skarmory immediately. Skarmory is declared out of battle. Barry thanks his Skarmory and returns it to its Poké Ball. He sends out Empoleon. Empoleon uses Hydro Cannon on Magmortar, injuring it. Despite knowing that his Pokémon will be injured under the effects of Spikes, Paul calls back Magmortar and sends out Ursaring. The Spikes from before inflicts a damage on Ursaring. Barry returns Empoleon. He chooses Hitmonlee. Paul tells Ursaring to use Bulk Up. Hitmonlee uses Mega Kick. Ursaring uses Hammer Arm but Hitmonlee dodges it by jumping on a rock. Ursaring uses Slash and Barry tells Hitmonlee to dodge it all. Then, Hitmonlee uses Close Combat. Ursaring uses Hammer Arm again and hits Hitmonlee. As Hitmonlee is about to crash onto a rock, Barry tells it to do its best. It jumps up high and uses Hi Jump Kick. It crashes to the ground and hits Ursaring with its other leg. Paul tells it to use Focus Blast. Although Hitmonlee dodges it by jumping behind a rock, the strong impact hits Hitmonlee. Ursaring uses Hammer Arm again, Hitmonlee counters it by using Blaze Kick, burning Ursaring. Ursaring activates Guts and uses Hammer Arm to counter Hitmonlee's Blaze Kick. The strong impact causes a smoke that clears soon after. Both Pokémon are seen standing up but Hitmonlee falls later. Hitmonlee is defeated. Outside the stadium, Team Rocket saw the battle outside the stadium on the TV screen. A Murkrow jokingly flies past them. James reminds them again of their store. Jessie says that nobody wants to buy, but James thought of a great idea. He runs off.
Barry chooses his Empoleon again. Paul tells Ursaring to use Slash and Empoleon uses Drill Peck. Both Pokémon are injured. Ursaring uses Focus Blast and Empoleon uses Steel Wing to reflect the attack. The Focus Blast is sent back to Ursaring, injuring it. Paul calls Ursaring back, and sends Electivire out. The Spikes hit Electivire. Dawn checks Electivire on her Pokédex. Dawn comments that Barry is about to lose. Empoleon uses Hyper Beam and Electivire counters it with Thunder. The attacks collide and causes a huge smoke. The smoke clears and shows Empoleon breathing heavily, needing to recharge after using Hyper Beam. Electivire uses ThunderPunch and Barry tells Empoleon to dodge it. Paul tells Electivire to continue using ThunderPunch, but Empoleon dodges them all. When Empoleon gets cornered, Electivire uses Giga Impact and Empoleon is hit at a point-blank range. Empoleon manages to stand up. Electivire uses ThunderPunch. Empoleon fails to dodge it, and is launched back many feet, smashing rocks in the process. Empoleon tries to get up. Barry yells it to continue doing its best, Empoleon hears it and its Torrent Ability is activated. Empoleon uses Hydro Cannon. Its Torrent Ability powers up its Hydro Cannon, which is strong enough to destroy the rocky terrain of the field. Ash, Brock and Dawn are all pleased with this break though, though Paul just orders Electivire to use Protect. Hydro Cannon hits the protective shielding and Electivire is unaffected by Empoleon's last resort. Empoleon has to recharge from the attack. Electivire finishes it the battle off with Thunder. Empoleon stands still, taking the damage of the Thunder. Barry yells out to Empoleon. Paul is declared the winner. Barry thanks his Empoleon for the great battle.
James rushes back to the store, bringing a big sack of things. Jessie and Meowth remove the ropes quickly. They began to promote their merchandise, which consists of many figurines of Paul's and Barry's Pokémon. A crowd appears, wanting to buy their merchandise. Team Rocket is thrilled.
As Paul is about to leave, Barry calls out to him. He asks Paul if they can battle again. Paul replies affirmatively. Barry is happy. Barry tells Ash that he will cheer for him on in his battle against Conway. His friends cheer for him too. Conway suddenly appears. Conway says that he will win but Ash denies. The episode ends with a scene of Ash and Conway.
When Barry's Skarmory used Spikes in this episode, it has the same effect as in the games (causing damage only to Pokémon switching into battle) as opposed to previous episodes when Spikes would instead causing damage directly against the opposing Pokémon.
When Team Rocket were selling their merchandise, they had a doll of Jessilina with a lollipop that she had been seen with in one of the Diamond and Pearl ending themes; Message of the Wind.
This episode marks the first time when the move Blaze Kick is used by another species of Pokémon than Blaziken.
At one point, a Murkrow flies by Meowth after he said that "it's a party at the stadium while out here you can hear paint dry." This is a reference to a common trope in Japanese media where a crow flies by a character after the character says something extremely obvious or extremely stupid.
The episode's name may be a pun on "casting a pall on Barry".