A bid on an online auction site, such as ebay, made by the person who's auctioning an item on an alternate auctioning account. This is used as opposed to a reserve limit, and/or when the owner of the item doesn't feel that the highest bid on their item is enough. That way, it either gets an even higher bid or it isn't sold then.
The man put his car up for auction on ebay with a starting price of $1 because he thought it might have a bid war. He was sadly mistaken, and with only a few hours left, the highest bid was only $1000. But luckily he had another ebay account and made a phantom bid for $5000 so that he would either get what he wanted or not lose his car.