The Unseen Peanuts
This strip was commissioned for the (New York) Giants Magazine, issue #4, which came out sometime in 1986. The strip is a direct reference to the baseball team and I expect that it was warmly received. I've always found it remarkable that there's probably plenty of other strips such as this, from Schulz, that appeared in publications all over the planet but more than likely won't be collected in the reprint series. It's a shame really, as it could make for an excellent extra volume - perhaps one of strips and other illustrations, such as toy design, boxes, cards, post cards - you name it, Schulz drew it.
In the meantime, from my scanner to your eyes, enjoy!