coo coo for cocoa puffs 

a strictly medical term, used to describe a patient or person that has delved into a realm of irrational, illogical and/or crazy thought processes; Affected with madness; insane to an exceeding degree characterized by weakness or feebleness; decrepit; broken; falling to decay; shaky; unsafe; foolish

See that guy trying to put that square peg into that round hole? I think he's gone coo coo for cocoa puffs!

coo coo for cocoa puffs by message_tied_to_a_brick June 30, 2004

coocoo for coco puffs 

May refer to a state of condition of lacking common sense, or being merely ignorant to a situation. Not acknowledging a situation

Why do I have to explain this to him over and over again, I don't want to be with him any more. He's coocoo for coco puffs.

coocoo for coco puffs by Denise (deneboo) November 8, 2007