The phrase "cocoa puffs" refers to a popular brand of chocolate-flavored breakfast cereal. It can also be used informally to describe someone who is acting crazy or silly. Full definition
She created a cute, little breakfast nook in the room next door, and I'm cuckoo for cocoa puffs over every little element she used in it! (theletteredcottage.net)
Among lots of other things, I am absolutely cuckoo for cocoa puffs over those metal picnic baskets on the right side of that picture! (theletteredcottage.net)
Homemade cocoa puff cereal from Purely Twins. (thefitcookie.com)