(: Add or to your mana pool.)
When Graven Pool enters the battlefield, sacrifice it unless you pay 1 life.
: Graven Pool becomes a 1/1 black and red Ogre creature with first strike until end of turn. It's still a land.
: Add 
or 
to your mana pool.)
: Graven Pool becomes a 1/1 black and red Ogre creature with first strike until end of turn. It's still a land.
