The above is by designer Dave Delisle, who dreams of an add on that would allow the Wii U to play DS and 3DS games. One that he calls the DSU.
The peripheral, which was first spotted on ALBOTAS, makes a lot of sense and for numerous reasons. As Delisle points out:
"We’ve already seen two instances of Nintendo releasing a device that would allow a console to play handheld games: The Super Game Boy for the Super Nintendo, and the Game Boy Player for the GameCube.
And looking at the hardware DNA of the Wii U, it is very conceivable that a third device is possible. The Wii U’s GamePad has a touchscreen, camera, microphone, and all the basic controls that would allow for the DS/3DS experience to be played on the console."
Unfortunately, as its creator also notes, the one feature that would be missing from 3DS games is the ability to display three-dimensional graphics. But given how 3D has always been more of an option than a requirement (plus most original model 3DS owners are used to having that feature shut off, lest they want to drain the battery in just a few hours), it's not the biggest loss.
But alas, it's only one person's crazy concept and not a real thing. Though, as noted, it's something Nintendo has done before and it would definitely expand the Wii U's library. Which is sorely needed right about now.