Enchant creature
Whenever enchanted creature attacks, put a +1/+1 counter on it. Then if it has three or more +1/+1 counters on it, sacrifice Ordeal of Clover.
When you sacrifice Ordeal of Clover, you may cast an instant or sorcery card from your hand or graveyard without paying its mana cost. If a card cast this way would be put into a graveyard this turn, exile it.