Amazon Delivery Guy

When Amazon Delivery Guy enters the battlefield, you may search your library for any amount of cards and exile them.
At the beginning of your upkeep, put a delivery counter on Amazon Delivery Guy. Once there are X+3 delivery counters on Amazon Delivery Guy where X is the amount of cards you exiled, you may cast each exiled card without paying its mana cost until the end of turn, then, put each exiled card into your hand.