Text (FE+errata): {1}, Exile two creature cards from a single graveyard: Put a 1/1 green Saproling creature token onto the battlefield. [Oracle 2009/07/08]
A "creature card" is a Creature card or Artifact Creature card. [D'Angelo 1999/05/01] Older cards of type Summon are also Creature cards.
The creature cards are removed from the game during announcement and as a cost. [Duelist Magazine #11, Page 56]
Token creatures that are destroyed go to the graveyard briefly, but are removed from the game before you can take any actions. You cannot use such creatures for Night Soil. [Aahz 1994/11/30]
Extended tournaments (see Rule 913) have banned this card since 1999/10/01.
