Courtesy of WWE:
WWE® AND WWE SUPERSTAR JOHN CENA® TEAM UP WITH POST PEBBLES CEREAL IN NEW PROMOTIONAL PARTNERSHIP
Parsippany, NJ / January 8, 2013 — Beginning today (for a limited time), WWE Superstar John Cena and Bamm-Bamm will replace Fred Flintstone on the front of more than 8 million Post Fruity Pebbles and Cocoa Pebbles cereal boxes as part of a promotional partnership between Post Foods and WWE. Pebbles Cereal, WWE and John Cena started their partnership in 2012 after WWE Superstar Dwayne “The Rock®” Johnson teased Cena about the brightly colored ring gear he wore, saying Cena looked like he was “running around like a big bowl of Fruity Pebbles.” This led to fans chanting “Fruity Pebbles” in arenas whenever Cena would enter the ring.