When Professor Kukui and Guzma were Hala's apprentices, they used to have battles with one another. Braviary used Brave Bird to defeat Golisopod, to which Kukui commented that Guzma needed to befriend his Pokémon. Elsewhere, Golisopod watched as Guzma was slamming his fist in fury, for not being able to defeat Professor Kukui.
Guzma sent Golisopod to fight Ash's Pikachu on the Pokémon School's grounds. Golisopod immediately started off with First Impression, which flinged Pikachu in mid-air. Pikachu counterattacked with Iron Tail, but Golisopod received no damage. The latter fired Pin Missile, which was stopped by Pikachu's Electroweb. Pikachu retaliated with Thunderbolt, which Golisopod managed to resist. Ash attempted to end the match by using his Z-Ring, having Pikachu use Corkscrew Crash Z-Move. However, Golisopod deflected the move. In an attempt to attack Golisopod with Quick Attack, Pikachu became poisoned by Poison Jab. Despite this, he went to attack with Iron Tail, but Golisopod countered the move with Pin Missile. As Pikachu used Quick Attack, Golisopod attempted to stop him with Poison Jab. Pikachu managed to dodge the attack, and hit Golisopod's soft spot. Guzma frowned, as Golisopod returned to his Poké Ball, due to its Emergency Exit ability.
Guzma used Golisopd to battle Lana's Primarina. Lana anticipated it to use First Impression, but Golisopod remained still. Thus, Primarina went to use Sparkling Aria, but Golisopod countered the move with Throat Chop, and prevented Primarina from using that attack. Primarina went to use Aqua Jet, to which Golisopod blocked the attack and held her, then used Poison Jab. The attack poisoned and weakened Primarina, who continued taking damage. To loose the hold, Primarina used Icy Wind on Golisopod's face, causing it to drop Primarina. Golisopod lost the hold over Primarina, who went to use Aqua Jet. However, she was stopped by Golisopod's Poison Jab, for in fact, the Icy Wind attack was simply absorbed by Golisopod's claws. Primarina attempted to run, but Golisopod held Primarina and continued using Poison Jab on her. Primarina attempted to get loose by firing another Icy Wind, to which Golisopod blocked the attack with Throat Chop. It proceeded by firing Pin Missile on Primarina, who defended herself with Surf attack. The impact of the attack caused Golisopod's legs to get frozen. Lana took the opportunity to have Primarina unleash Oceanic Operetta Z-Move. In that moment, Golisopod used Liquidation to slash the bubble in half, destroying the Z-Move and Primarina ended up getting hit by Liquidation and was defeated.
Guzma used Golisopd to battle Ash's Torracat, after Scizor used U-turn to switch places with it. Golisopod resisted the Fire Blast attack, then use Liquidation to hit Torracat. As Golisopod repeated its attack, Torracat used Fire Fang to inflict some damage on Golisopod, but was blown away by the latter's Throat Chop. Torracat went to use another Fire Blast, but was countered by Golisopod's Liquidation. Torracat avoided the attack, and used Flame Charge to evade Golisopod's Pin Missile and strike it, tackling it down. While Golisopod was down, Torracat used Fire Fang to inflict some damage to it. As Torracat got hit by Throat Chop, it retaliated with Revenge, causing more damage to Golisopod. Torracat went to use another Flame Charge, but this time, Golisopod's Pin Missle stroke it. The two sides then collided with Liquidation and Revenge. Torracat went to use another Fire Blast. Guzma ordered Liquidation, but Golisopod was overwhelmed and returned back into Guzma's Poké Ball, and Scizor was forced out, who took the hit. Guzma became angry that Scizor fainted due to Golisopod's cowardice. Guzma sent Golisopod out again and scolded it for using ability to dodge that attack, being a coward, and for letting its teammate get beaten as they continued their fight.
Guzma reminded this was the last chance for Golisopod to redeem itself. Golisopod used Poison Jab, which Torracat attempted to dodge, but got poisoned by the attack. As Torracat evaded Golisopod's Throat Chop, it took damage from the poison. It went to use Fire Fang on Golisopod, who shrug Torracat off and slammed it to the ground. Torracat was defeated, so Ash sent Pikachu to confront Golisopod. Golisopod went to use another Poison Jab, but Pikachu evaded the attack. However, as Pikachu was in mid-air, Golisopod used Throat Chop, which badly hurt Pikachu. Pikachu stood up, and used Electroweb against Golisopod's Pin Missile. He went to use Thunderbolt, but Golisopod blocked the move with its claws. However, Pikachu quickly went to topple Golisopod in mid-air with Iron Tail, and electrocuted it badly with Thunderbolt. Despite this, Golisopod was able to battle, having a malicious glint in its eyes. Ash had Pikachu unleash the Z-Move, Gigavolt Havoc, on Golisopod, who remained in its place, defending itself. It endured the attack, while Guzma realized that Golisopod wanted to give its best. Screaming out, Guzma declared he would show what they had: Golisopod fired Pin Missile, which Pikachu evaded with Quick Attack. The two sides clashed with Liquidation and Iron Tail, then Golisopod used its claws to counter PIkachu's Electroweb. As Pikachu avoided another Poison Jab. In the finam moment, Pikachu clashed with Golisopod, as the two sides used Iron Tail and Liquidation. However, Golisopod fainted, to which Guzma lost the semi-finals. Guzma went to his Golisopod and helped it stand back up. He called it into its Poké Ball and silently walked away from the battlefield.