Now we know its controller was, too, by way of the US Patent and Trademark Office's database, which also contains related drawings. One shows what this line-art person is playing (a tennis game with Mario) and the other is the proverbial smoking gun: a Wii remote and receiver connected to a GameCube, which is, in turn, connected to a TV with sensors attached. Check them out after the break.
Nintendo Wii console
Nintendo Wii Remote controller