Hyperkin's SmartBoy April Fool's joke is real
On May 31, Hyperkin "leaked" concept images of what many thought to be an April Fool's joke: the SmartBoy, a controller which would allow you to play original Gameboy carts on your Smartphone.
The very next day, Hyperkin revealed that the SmartBoy concept images were more of a test of the potential market for such an item. And given the responses, the SmartBoy would be going into full production.
The first protoype of the SmartBoy was revealed at E3 2015. According to Nintendolife, the SmartBoy acts as a ROM dumper, essentially copying the data of the game over to the phone. A GameBoy emulator was used in the demonstration.
A significant question does remain: if Hyperkin is making this product, will Nintendo file a claim for copyright infringement? Nintendo has a history of doing so even for fan-made products, including a 3D printed Bulbasaur planter. Only time will tell.