Companies file all sorts of patents, so there's every chance that this particular device will never see the light of day.
However, combined with this week's networked computing patent, a fresh application from Nintendo could point to yet another big innovation from the platform holder for its next console the NX.
US patent application 20150355768 details an oval controller with two analogue sticks and shoulder buttons, as well as a speaker. That's where the normalities end, however. The whole face of the device is a touch enabled display screen, allowing for custom buttons to be displayed along with animated graphics.
The controller would also be able to display other content, such as a browser. Also integrated are gyroscopic motion controls and a storage card slot.
The documents says that the screen could be either LCD or OLED, and could use the 3DS' 3D technology. Nintendo has previously been linked with Sharp's Free-Form Displayers, which would seem suitable for this quite specific task.
Here's a better look at some of the details: