Each player chooses a card in their hand. Then each player reveals their chosen card. The owner of each creature card revealed this way with the lowest mana value puts it onto the battlefield.
2004-10-04
Creature cards which are revealed but are not the lowest cost, or any non-creature cards revealed remain in their owners' hands and stop being revealed.
2004-10-04
You don't have to choose a creature card, but choosing a non creature does nothing except maybe bluff your opponent.