Seel is a pinniped Pokémon with a thick hide covered in bluish white fur. It has a pale tan maw with a large red tongue and a pair of tusks on its lower jaw. It has circular eyes and a black nose that is capable of closing when it swims. There is a small horn on its forehead, which it uses in combination with its tusks to bore through ice floes. It has two flippers on its chest, and two more on the end of its tail. When the tail is raised, it resembles a waterspout.
Seel lives on icebergs in frigid ocean waters. Its warm fur and thick hide allow it to swim in waters as cold as -40° Fahrenheit (-40° Celsius). It thrives in these cold environments, becoming more active as the temperature drops and tires easily in warm waters. Preferring to sleep during the day, it hunts for prey under sheets of ice in the late day and evening hours. While it is a graceful swimmer, it is awkward and struggles to move on dry land.
Major appearances
Multiple Seel debuted in The Water Flowers of Cerulean City, under the ownership of Misty and her sisters at the Cerulean Gym. One of them evolved into a Dewgong in The Misty Mermaid.
Other
A Seel appeared in Misty Meets Her Match, under the ownership of Mahri. It was caught in a whirlpool alongside its Trainer, but they were both saved by Misty and her Staryu.
Minor appearances
A Seel appeared in Pikachu's Vacation as one of the Pokémon seen at the Pokémon Theme Park.
A Seel appeared in Slowking's Day, where it was living in the ocean surrounding Shamouti Island.
Multiple Seel appeared in Showdown at the Po-ké Corral, where they were among the Pokémon living at Professor Oak's Laboratory. They reappeared in The Rivalry Revival.
A Seel appeared in Misty's fantasy in Bye Bye Psyduck.
Multiple baby Seel appeared in The Joy of Pokémon as residents of an unnamed island.
Multiple Seel appeared in The Power of One.
A wild Seel appeared in Pikachu's Rescue Adventure.
A Seel appeared in Slowking's Day, where it was living in the ocean surrounding Shamouti Island.
A Seel appeared in a fantasy in The Totodile Duel.
A Seel appeared in Snorlax Snowman.
A Seel appeared in The Joy of Water Pokémon as an inhabitant of Lake Lucid.
A Seel appeared in Around the Whirlpool as one of the Pokémon stolen from the Pokémon Center of Blue Point Isle.
A Trainer's Seel appeared in Octillery The Outcast as one of the Pokémon participating in the Whirl Cup. Ash and Totodile went up against it in a qualifying match and won.
Multiple Seel appeared in Bulbasaur... the Ambassador!, where they were among the feuding Pokémon at Professor Oak's Laboratory.
A Seel appeared in The Legend of Thunder! as one of the Pokémon seen at a Pokémon Center.
Multiple Seel appeared in Nice Pryce Baby, under the ownership of Pryce. They were seen at the Mahogany Gym.
Multiple Seel appeared in the opening intro of Celebi: The Voice of the Forest, which was reused for Pokémon Heroes: Latios & Latias.
Multiple Seel appeared in Destiny Deoxys.
A Seel appeared in Pokémon Ranger and the Temple of the Sea, under the ownership of Lizabeth and her family. It was among the Water-type Pokémon used for their Marina Underwater Pokémon Show.
A Coordinator's Seel appeared in Once More With Reeling!, where it was seen participating in the Terracotta Contest. It created an ice sculpture of a Glalie using Ice Beam.
A Seel appeared in Up Close and Personable! as a resident of the lake near the Pokémon Summer Academy.
A Seel appeared in Historical Mystery Tour!, under the ownership of a Clown. It was seen standing on a ball with one fin.
A Seel appeared in I Choose You!.
A wild Seel appeared in Alola, Kanto!, where it was among the Pokémon seen at Professor Oak's Laboratory.
A Trainer's Seel appeared in SM129, where it competed in the Battle Royal round of the Manalo Conference but ended up losing.
In the Pokémon Adventures manga
Seel is the first Pokémon Lorelei owned, which debuted in Can You Diglett?. As a child, Lorelei saw her Seel become poisoned due to the effects of nearby industrialization. Agatha, who was passing by, healed Seel using her Gastly. This encounter with the negative effects that humanity had on Pokémon would be the motivation Lorelei had to join the Elite Four in a plot to destroy all of humanity years later.
Pryce owns two Seel that assist him in sculpting ice. They first appeared in Irked Igglybuff and Curmudgeonly Cleffa.
A Seel appeared in The Last Battle XIII as one of the Pokémon sent to participate in the fight in Ilex Forest.
In the Pokémon Zensho manga
Satoshi received a Seel from Misty. He releases it upon his arrival in the Seafoam Islands.