Video Game accessory company HORI has announced they will release a
Pikachu Classic Controller for Wii U/Wii (クラシックコントローラー for Wii U/Wii ピカチュウ) in Japan on December 20th, 2014. The controller is yellow and styled to look like Pikachu but despite the fact that it looks like a GameCube controller, it is a Classic Controller and it is plugs into the Wii Remote port and is not compatible with the Super Smash Bros. GameCube Controller adapter. It also comes with a Wii Remote plate and turbo button. The Pikachu Classic Controller will retail for 3,434 yen.
Source:
http://www.hori.jp/products/WiiU.php