Are you looking for answer to real star wars based breakfast serial sold in 80s era?
C-3PO’s by Kellogg’s were similiar to Cheerios in appearance, they were having form of numeral eight
Cereal pieces are designed as tiny figure-eights.
Kellogg’s introduced C-3PO’s just one year after the third film of Star Wars’s original Star Wars trilogy appeared in theaters.
The boxes also contained Plastic Rebel Rockets, Star Wars Sticker/Trading Cards or cut-out Star Wars Masks There was also the possibility of a giveaway for Kenner Star Wars action figures.
Kellogg’s also made small, individual-serving C-3PO’s boxes that could be purchased in the form of an assortment of cereals. These boxes are rare and considered to be rare among collectors of cereal boxes.
Trusted Source : https://cereal-graveyard.wikia.org/wiki/Kellogg%27s_C-3PO%27s