If you'd like to play doubles in Mario Tennis Open with someone who looks vaguely like a tennis ball in hue, we can help with that. Nintendo shared the above QR code exclusively with Joystiq, and now we're sharing it with you. From within the 3DS game, you can snap a picture of this code and unlock a yellow Yoshi for your game.
We hope you love it! Get it – because "love" is a tennis term ... but wait, "love" is bad in tennis. We're going to have to think about this joke and get back to you. Anyway, here's that Yoshi.