Blood Clock
Saviors of Kamigawa — rare
Artifact
Blood Clock rulings:
2005-06-01: A player with less than 2 life can’t pay 2 life and must return a permanent.
2005-06-01: A player who controls no permanents doesn’t need to pay 2 life (although that player can choose to do so).
2005-06-01: The choice of which permanent to return or whether to pay life is made as the triggered ability resolves.