• English / United States: Clay's Krokorok
• Japanese / Japan: ヤーコンのワルビル
• Japanese (Romanized) / Japan: Yacon no Waruvile
• Japanese (TL) / Japan: Yacon's Waruvile

Clay's Krokorok was the first Pokémon Clay used to battle against Ash Ketchum during his gym battle. Clay's Krokorok was paired up against Ash's Oshawott as Ash's Pikachu initially wanted to battle it but Ash Ketchum realized that an Electric type against a Ground type would be a bad idea.

At the beginning of the battle, Clay's Krokorok had the upper hand as its Sandstorm managed to get sand in Ash's Oshawott's eyes and it also made it harder for Ash's Oshawott to accurately attack. Clay's Krokorok managed to hit Ash's Oshawott with a Bite and a Stone Edge attack but it wasn't enough to knock it out. Ash's Oshawott used Water Gun to clear up the Sandstorm and then it began its counterattack. Clay's Krokorok was repetitively hit with multiple attacks from Ash's Oshawott including a super effective Aqua Jet and Razor Shell combo that ended up being too much for it and it was knocked out.