Petrel used his group of Koffing to attack Silver when he arrived in the Dragon's Den. They later also attacked Clair when she arrived. Silver was able to defeat the group of Koffing with his Honchkrow and his Weavile and took the plate they carried.
Later on at the Safari Zone, while Petrel was spying on Silver and Eusine, his Koffing were surrounding him. A little while later, Eusine's eyes and nose started to run and couldn't stop coughing. Silver looked it up in his Pokédex and noticed that it was Koffing's gas. The Koffing's gas started to come in thick and fast as Petrel revealed himself to them. After the introduction from Petrel, Silver sent out his Weavile and ordere it to use Icy Wind, which froze the holes on the Koffing, preventing anymore gas coming out of them. Petrel stated that it was too late as the gas had already surrounded them and used the gas to his advantage. As Petrel gave Silver a choice, his Koffing were behind him.
None of Koffing's moves are known.