Someone who can speak quite quickly who lists the highest bids made so far at auctions and who they were by and tries to provoke someone richer in the audience to bid more for it. If he doesn't succeed, he slows down and goes, "Going once... going twice... SOLD!" This is ostensibly done to give people a last chance to interject and make a higher bid but that never happens except in movies when the rightful owner bursts in through the door.