Corn Flakes

From Muppet Wiki

Kellogg's Corn Flakes featured a promotion for The Muppet Movie on cereal boxes sold in Australia in 1979. Muppet stickers were included in each box, which could be used to decorate illustrated scenes on the back of the boxes.

In the United States, the Muppet Movie cereal box promotion was handled by General Mills, on Cheerios boxes.