So I recently bought a Gameboy colour from eBay (I'm actually returning it soon because it didn't have the battery cover and it was meant too, seems stupid to return it but ) and then I noticed while looking on eBay for a different one, the one I had is different to all the others. It has this circle shaped grey piece of plastic glued over the D pad. It looks like a D pad thing but its round. It has a D pad shaped sort of molded into it.

Anyway I've looked on the internet and haven't found anything else like it, and was wondering if anyone new if it was an official kind of attachment or anything, or just some random thing someone glued to it? Its kinda weird. XD
Thanks

I believe that was an attachment for the GBC iirc. However its not suppose to be glued on.

The only such device I've heard of was for a Super Famicom game called Libble Rabble, a port of an early '80s arcade game that required moving two characters at once. That one was meant to sit on top of the ABXY buttons (used as a second D-Pad in the default control scheme).

But I don't know what a GBC game would need such a device for.