Whispering Soil

Empty {1}{u} (You may cast this card for its empty cost. If you do, exile it as it resolves. During your precombat main phase, if an opponent cast no spells last turn, you may cast the exiled card without paying its mana cost. Empty only as a sorcery.)
Create a 1/1 blue spirit token with flying. If Whispering Soil was cast from exile, create X 1/1 blue spirit tokens with flying instead, where X is the number of creature cards and lands in your graveyard.