Dewgong first appeared alongside its trainer in order to stop the Red Gyarados from attacking Mahogany Town. It stopped Gyarados' Hyper Beam with a powerful Ice Beam. Dewgong was also used to battle Ash's Phanpy where it won with a single Ice Beam, freezing Phanpy.
Pryce used Dewgong to battle Ash's Cyndaquil. Cyndaquil started with Flamethrower, though Dewgong dived into the battlefield's pool to evade the attack. Soon after, Dewgong retaliated with Ice Beam; Cyndaquil attempted to dodge, but tripped over and got frozen. Fortunately, Cyndaquil ignited the flames on its back and melted the ice away, then dodged Dewgong's Aurora Beam. Dewgong repeated its attack, but Cyndaquil avoided the attack. Cyndaquil also repeated Flamethrower, but Dewgong went into the pool to dodge. Using Quick Attack, Cyndaquil dived into the pool, where Dewgong was about to use Headbutt. Cyndaquil negated the attack with Swift and defeated Dewgong with Flamethrower.