(Hollow Stand isn't a spell.)
Hollow Stand enters the battlefield tapped unless you sacrifice a Black permanent.
: Target player exiles a card from his or her graveyard.
: Add or to your mana pool.
Sacrifice Hollow Stand: 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.
