An extremely loud that makes your butthole explode and rumble, and when it comes out it sounds like you accidentally stepped on a duck and it screamed. Usually happens when you hold a fart until you can't hold it anymore.

The sound of a particular fart caused by overly compressed butt cheeks. This will occur due to the person attempting to slip out a silent squeaker so as not to draw attention to his or herself. Odds are a quack-like sound will result from this expulsion. There will always be at least one person who will notice and call you out immediately.

A really loud, smelly fart that almost sounds like a quack.