We’ve seen some images and rumors about an odd add-on for the Nintendo 3DS. Engadget alerts us that the peripheral has been listed on Nintendo’s Japanese web site with an expected ship date of December 10th retailing for ¥1500 (US$19.50). It will require a AAA battery. The device adds an analog stick to the right side of the controls, but I’m not too clear on what else it does. The listing also include a compatibility chart specifying what games that will work with the add-on (and their launch dates). Games include, but are not limited to Monster Hunter Tri G, Biohazard: Revelations and Metal Gear Solid Snake Eater 3D.

[Image and News from Engadget]