(Timberland Swamp isn't a spell.)
When Timberland Swamp enters the battlefield, sacrifice it unless you pay .
: Target player exiles a card from his or her graveyard.
: Add or to your mana pool.
Sacrifice Timberland Swamp: Add or to your mana pool.
.
: Target player exiles a card from his or her graveyard.: Add or 
to your mana pool. or to your mana pool.
