
I thought it ended at CUCKOO.
The Big Bang Theory Season 1, Episode 15

It's like the world's
fattest CUCKOO clock.
The Big Bang Theory Season 7, Episode 23

The newly hatched CUCKOO
eats all the food...
The Big Bang Theory Season 1, Episode 15

was for CUCKOO pills.
The Big Bang Theory Season 7, Episode 7

By that standard,
Penny is CUCKOO for Cocoa Puffs.
The Big Bang Theory Season 4, Episode 9