Obsidian Debris enters the battlefield tapped unless you control one or more creatures.
: Add to your mana pool. Obsidian Debris doesn't untap during your next untap step.
, , Sacrifice Obsidian Debris: Target creature gets -2/-2 until end of turn.
: Add 
to your mana pool. Obsidian Debris doesn't untap during your next untap step., , Sacrifice Obsidian Debris: Target creature gets -2/-2 until end of turn.
