look up any word, like bae:
 
1.
Ketchup or Catsup product that most likely will clog your arteries until death strikes you. Estimated to have 2 whole sticks of butter in every bottle along with other fattening agents.
Originated from Mark's basement. It was spray painted in the side of the stairs.
Get your "fatsup" in the stores.
by xSchaefx June 22, 2004