Glistening Extractor enters the battlefield with four oil counters on it. At the beginning of your upkeep, if there are one or more oil counters on Glistening Extractor, seek (To seek a card, put one at random from your library into your hand.) a card with mana value equal to the number of oil counters on Glistening Extractor, then remove an oil counter from Glistening Extractor.