You get a Shiny Eevee, but it's glitched in such a way that you can't trade it to any other game, it tends to disobey orders, and it can't learn anything but normal-type moves. It also can't evolve.
Granted, but this keyboard cat(not the YouTube thing) is also a real cat, and in order to use it, you have to follow it wherever it goes, even the littler box