(Murmuring Hollows isn't a spell.)
When Murmuring Hollows enters the battlefield, sacrifice it unless you pay .
Green creatures get +1/+1.
: Add or to your mana pool.
: Add to your mana pool. Put Murmuring Hollows on top of your library.
.
: Add 
or to your mana pool.: Add 
to your mana pool. Put Murmuring Hollows on top of your library.
