If you remember the old days of Mad Magazine (and/or possibly the current run) you may remember the last page always had the "fold-in" gag. It was a picture that took on new meaning when you folded the page to reveal a new image hidden in the drawing.
I'm not sure that's a great explanation, but come on, you know what it is. Probably because you've also seen it in ads for some of your favorite products. In fact, our pals Count Chocula and Frankenberry used the format to announce the return of an old friend:
Like most of the old Mad fold-ins, you can probably guess what the gag is without folding it. But who wants to live in a world where you don't fold things? Let's fold! Fold hard!
Just like in Mad, the edges never seem to line up perfectly but maybe that's part of the charm. As you probably guessed, this was an add announcing one of the many returns of Yummy Mummy! He was the next best thing when Frute Brute wasn't available.
Several brands wanted in on the fold-in action and you can find several of them in old comic books. As a bonus, here's one from Chips Ahoy:
You can probably see where this one is going but let's take a look at it after the foldening:
If you guessed it was going to be something cookie related, you were right! It kind of looks like some kind of primitive Pac-Man/cookie hybrid puking out brown lines or maybe shouting. I want to give Pac-Cookie a name but I'm afraid I'll grow too attached.
Anyhoo, I'll post more fold-ins if/when I find any more.