As odd as it sounds, Pokémon Rumble U doesn't feature a single Pokémon. Instead, the Pikachus and Charizards you encounter are sentient toys equipped with the attacks and elemental affinities of their namesakes. They each look largely as you'd expect, but this toy-based quirk lends itself well to Nintendo's overall strategy for the game, which involves releasing a series of action figures which can be used as playable characters in Pokémon Rumble U.
From a corporate, money-making perspective, this seems like a brilliant, almost nefarious scheme to part parents from their paychecks. Unfortunately, the potential of marrying the addiction of Pokémon with the appeal of physical toys loses much of its appeal in the face of overly simplistic gameplay - even for a Pokémon spin-off.