Late last week a Nintendo patent application for a strange U-shaped controller surfaced in the gaming forum NeoGAF. The patent application, which was reportedly filed in October of 2014 and has been roughly translated into English, suggests that Nintendo had plans for a motion-based controller with a variety of fitness-related sensors, including a gyroscope, acceleration sensors, and temperature sensors.

"The main object of the present invention is to provide a novel training equipment, training system and an input device," the application reads. It references use of a balance ball, and is also referred to as an "exercise appliance and health appliance."

Even after reading a good part of the application, the horseshoe-like device is still shrouded in mystery. Here are five things the patent application might actually be for:

1. Some type of dedicated health controller that will work with Nintendo's next big console, codenamed NX. "NX" is expected to come out by the end of this year and has been described by Nintendo as a something "unique and different," not just the "next version of the Wii or Wii U."

2. A non-wearable wearable that would work with Nintendo's stalled "quality of life" health platform, which the company first spoke about in 2014 and said would launch in April 2015 (but then never did), and now its fate seems totally up in the air...

3. An hand controller that will work with a yet-to-be-announced Nintendo AR / VR headset, which will transport us all into a magical world of warp pipes, labyrinth dungeons, and rainbow roads.

4. An actual horseshoe — but a "smart" one. If there are apps for logging saddle hours and tracking your horse's weight, why not make a horseshoe that will wirelessly send all of that data to an app? Horses need Fitbits, too? It would be a slight deviation from Nintendo's, um, stable of products, but Nintendo has done stranger things before. (Okay, we don't really think it's a horseshoe.)

5. Nothing. Tech companies file patent applications all the time. And Nintendo has a history of filing bizarre patent applications. This U-shaped motion-sensing controller device may never come to market.

Then again, maybe we'll all be sitting on balance balls holding boomerang controllers in our hands, tracking our activity levels — or inactivity levels — soon enough.