Expression used when referring to someone that is a duck. Simulates the sound that the animal known as a duck makes. Appropiate when out in public and you see a duck but don't want to risk someone noticing the fact that you are insulting them. Orgin is the show Growing up Gotti, where there is the biggest example of a duck, a gentleman whose actual name is quack quack.
When someone has an extreme urge to watch one of the MightyDucks movies, very common in drunk/high teenagers.
Guy 1: "Nate, you want to watch the Mighty Ducks?"
Guy 2: "Yeah bro, I have a serious case of the Quacks."
Guy 1: "Yeah knucklepuck that shit man, straight Bombay style."