a bad penny
A person with no value. Typically used in the proverb "A bad penny always turns up." A: "I don't think we'll see Todd again now that he's been disgraced at work." B: "You never know—a bad penny always turns up."
bad penny
a worthless person. Wally is a bad penny. Someday he'll end up in jail. My little brother is a real bad penny. Every time he shows up, he wants to borrow money.