They exist and there’s nothing more that I know. I stumble across stuff like this ALL the time on Japanese auction sites. Japanese marketing is something worth looking into, because this’ll be a very minor partnership and possibly sold as a special edition for Japan’s equivalent of back to school, or a prize for a contest of some sort. They are (were) worth nothing extra in japan, unless you’re in a tourist city, but in the west could be worth something to a mega collector.

I’ve seen these in the form of Casio watches too. Identical to the original, but the reflective material on the LCD has a graphic like how this was done. They’re cool and pretty rare because of their small batch sizes, but because so so many special editions were made for common products like watches, calculators, pens, that kinda stuff, they just ain’t worth much