Character: Jugon (Yanagi)

Dewgong's name is derived from the real animal which has a similar, but much larger, body: the dugong. In the beta versions of Red/Blue, Dewgong's name was originally going to be Manaty, a reference to the manatee. The Pokémon first appears in the arsenal of a trainer named "Allison" outside of Saffron City, who cites her similar body fat percentage as a reason for her choosing to utilize the Water/Ice type Pokémon.

While on-route to the island where only the Dragon Pokémon Kairyu live, Go encountered a Dewgong that he tried to catch. He had brought an entire backpack of Poké Balls to catch Pokémon that day but he ended up using all of them to finally catch Dewgong.

Ash and Go rode on its back to try to get to the island but a female Dewgong swam by which got Go's Dewgong infatuated with it and it started going after her but right into a storm. Ash and Go got knocked off and into the sea but thankfully a ground a Dragonite rescued them. Later on at the island, Go noted that Dewgong was still heartbroken.

Prima's Dewgong is a powerful Pokémon that knows Aurora Beam and was seen taking part in one of Prima's Lectures.

After capturing Neesha's Dewgong, Mewtwo put it into his cloning machine and made his own Tentacruel which he later commanded to fight its original counterpart.

Daisy's Dewgong made its first and only appearance in the episode The Misty Mermaid. It was in an underwater ballet written by Violet, one of Misty's three sisters.

After successfully attacking Jessie's Arbok, it evolved and afterwhich froze Team Rocket with its Ice Beam attack. In the end, the show was saved by Daisy's Dewgong. Unfortunately it hasn't been seen since and most likely remains at the Cerulean City gym.

Neesha is one of four Pokémon Trainers who managed to brave Mewtwo's storm to get to New Island by riding her Dewgong.

Dewgong is a Pokémon that Neesha took to New Island after Neesha was invited to meet the "World's Greatest Pokémon Trainer".

Mewtwo captured Dewgong and made a clone of it for himself.