(: Add or to your mana pool.)
Flat Barrens enters the battlefield tapped unless you pay .
, , Sacrifice Flat Barrens: Prevent all combat damage that would be dealt this turn.
, Sacrifice a Swamp: Add to your mana pool.
: Add 
or 
to your mana pool.)
., , Sacrifice Flat Barrens: Prevent all combat damage that would be dealt this turn., Sacrifice a Swamp: Add to your mana pool.
