Nintendo Cereal System was Cereal manufactured by Ralston Cereals in the late 80's that featured characters and items from the Mario and Zelda universe. Two of the most popular NES games at the time, taking the form of shapes.
Included in the Mario section were fruity- flavoured Mario's , Super Mushrooms, Goombas and Koopa Troopa's
Included in the Zelda section were berry-flavoured Link's, Shields, Hearts, Boomerangs and Keys..
There was one sticker in each box.
On the back panel, there were twelve sets of Nintendo Power Cards included.
There were also now-defunct offers for NES Power Pads and a Super Mario Cereal Bowl on the back.
Nowadays, the Cereal boxes are seen as collector's items and can range from about $100 on online auctioning sites such as eBay and Amazon.