Help me figure out what this mystery item is?! Found while metal detecting.

I was metal detecting at a park in Fullerton, California where I never did get the name of the park and while there, I found this little thing with Korean inscription on the side. I think it's for a game...maybe a Nintendo thing? I'm not sure. I'm pretty positive the other interesting item I found was a lighter. I was using my Samsung Galaxy S3 to film and a Garrett Ace 250 with White's Bullseye TRX pinpointer for metal detecting. The items I found intrigued me and I figured you'd like them, too, so I shared ;) Enjoy!