Pikachu

Pikachu is one of Pooh's friends and Ash's best friend on Pooh's Adventures of Pokémon: Mewtwo Returns Pooh, Pikachu and the others got blowed away on Team Rocket's balloon and landed on an island on Mt. Quena and helped Mewtwo escaped from Giovanni's machines.

Trivia:

Pikachu had it's first apperance in Pooh's Adventures of Mulan

And Pikachu got invited by Pooh in Pooh's Adventures of The Secret of NIMH

Pikachu will join Pooh and the others on the Pooh's Adventures of STAR WARS saga

and Pikachu wiil join Pooh and friends in Winnie the Pooh Goes Back to the Future

Pikcahu will join Pooh and his friends in Winnie the Pooh and The Chronicles of Narnia: The Lion, the Witch and the Wardrobe

Pikachu will join Pooh and his friends in Pooh's Adventures of The Land Before Time II: The Great Valley Adventure

Pikachu will join Pooh and the others in Winnie the Pooh Meets 3 NinjasPikachu will join Pooh and his friends in Pooh's Adventures of The Karate Kid, Part II