The term used to describe the fat, ugly, skanky or any combinations of the three that you hook up with that turns your luck around after months of good fortune with attractive women; Opposite of Slumpbuster.
When I was in my late twenties, I was having good luck with all of the hot sorority girls. I got drunk one time and had my way with a fat chick. God damn that Slumpstarter! I haven't had any action in six months.