Mythical Island was the first themed booster pack set in the game. It introduced a number of new mythical Pokemon, such as Celebi and Mew ... on Arceus and other legendary Pokemon, including ...

While this Pokemon ... like Mewtwo. Celebi may not be as big as Lugia, but it’s a mythical psychic-grass type Pokémon with innate abilities on par with any other powerful legendary Pokémon.