What is Creeping Fatty?
1.
A girl who begins their stay in your life looking fit and trim, and, over time, gains weight to the point where they are fat. This is never good, because you have become attached to their personality, but hate their looks. A trap.
Nick: "poor justin. Looks like tonia was a creeping fatty after all!"
Brian: "yeah.... I kinda feel bad for both of them..."
See
