There was a recent discussion about playing chess with Grim for someone's life. Many didn't know it was possible. Thanks for the picture of it!
That may be a reference to another media. I read a book when I was younger about a kid playing chess with the devil to save his half brother and uncle, after said devil had already killed the rest of his family. I have also heard it referenced in other stuff, like lolcats pictures and on other forums. I'll look around and see what I can find.
-Edit- I found info easily. Here's a few links.
http://answers.yahoo.com/question/index?qid=20090125203448AAb2Dd3 This is a simple story about the devil and a man playing in a painting, apparently told in Christian ministries for a long time. However...
http://www.chessville.com/reviews/SchachaufOlgemalden.htm In this link, the picture second down, to the right, you'll see death losing to someone at chess. This is probably what the reference is about...Though I wonder if you could play with Grimmy on a different platform for a soul...
Okay, I'll get back on topic. Sorry.