When Quack Quack was still in an egg, his parents were killed by a hunter. A group of scientists picked him up and made several experiments on him. As a result, he is indestructible, super-smart and addicted to yogurt.
Quack Quack is very forgiving, as he seems to forgive Mr. Cat for his constant abuse of him (although in episodes such as "Let's Play Ki Cé Ka Raison" and "Let's Play Figurines" he does get revenge on him), and he forgives Olaf in "Let’s Play Frosted Christmas – Part 2" even though Olaf kidnapped him and his friends.
He is also willing to take any amount of abuse for his friends' sake.
He is afraid of only three things: doctors (thanks to the scientists who experimented on him), never finding his creator, and expired yogurt.
He is one of the show's smartest characters. He is extremely lucky and can win at almost any game. He is also physically very strong. Due to having numerous science experiments performed on him, he cannot be destroyed.
He also has robot-like functions, for example, lights can come out of his eyes, he can give out soda cans like a vending machine, and he can operate as a fan or propeler by rapidly spinning his arms.
He is addicted to yogurt. The episode "Let's Play Trap-Trap" showed that if he goes for even one hour without yogurt, he experiences withdrawal-like symptoms, behaves like a zombie and hallucinates.
Quack Quack doesn't speak, and instead only says "Quack". This seems to be some kind of duck language, as suggested in "Let's Play Hallo, Hello, Hola!". Kaeloo and Eugly can understand him perfectly. Mr Cat can understand him most of the time, but there are times when he needs Kaeloo to translate for him. Stumpy can only sometimes understand him, and Pretty usually cannot.
Quack Quack is a yellow duck. He has blue eyes with purple eyelids. His body is covered in stitches, since he has to be stitched up after being cut up or blown to pieces. He typically wears a pair of blue underpants.
Role in the show
Quack Quack is frequently tortured by Mr. Cat, which is the usual reason for Kaeloo's transformations.
He is very smart when it comes to science, math and the like (but not very much when it comes to common sense), and he uses his intelligence, robotic abilities and indestructibility powers to help the others when necessary. He is also the boyfriend of Eugly.
- Quack Quack hinted to be the youngest character on the show.
- Quack Quack is the only bird in the main four.
- The expository comics revealed that he lives in a bathtub house, but it has never been seen on the actual show.
- In "Let's Play Simon Says", it was revealed that he wears a diaper under his underpants.
- When deprived of yogurt, Quack Quack undergoes withdrawal-like symptoms turns into a "zombie" of sorts, as seen in "Let's Play Trap-Trap".
- Quack Quack does not have teeth (as noted in "Let's Play Doctors and Nurses"), but whenever he is turned into a zombie (or deprived of yogurt) he suddenly has teeth.
- He is the only one of the main four to wear any clothes (not counting gloves and shoes).
- He is the only character to have blue eyes (Pretty's are green, Eugly's are hidden from view by her hair, and the others have red eyes).
Quack Quack's gallery can be viewed here.