(: Add or to your mana pool.)
Flat Cavern enters the battlefield tapped unless you pay .
: Flat Cavern becomes a 2/1 white and black Bird creature until end of turn. It's still a land.
: Add 
or 
to your mana pool.).: Flat Cavern becomes a 2/1 white and black Bird creature until end of turn. It's still a land.
