Wailmer

Wailmer is a Water-type Pokémon from the Hoenn region. It evolves into Wailord when fed 400 candies.

Trivia

 * Along with Magikarp, Swablu and Meltan, Wailmer is the Pokémon in the game that needs 400 candies to evolve which is the largest amount of candies to evolve in the game.