When Reef Keep enters the battlefield, sacrifice it unless you pay .
: Add or to your mana pool.
: Add to your mana pool. Put Reef Keep on top of your library.
: Return Reef Keep to its owner's hand.
.
: Add 
or to your mana pool.: Add 
to your mana pool. Put Reef Keep on top of your library.: Return Reef Keep to its owner's hand.
