Guy 2: Those Loan Sharks knocked his teeth out, and put his cat in the dishwasher!
Guy 1: He shoulda paid up!
The name comes from the ruthless and violent popular image of sharks, and basically assumes the lender hasconnections with organized crime.
Can also sometimes be applied to one who always seems just a bit too mercenary in thier "assistance" of friends.
Bobby said he wouldn't give me a ride to work unless I gave him $15 for gas... What a loan shark.