Howltooth Flats enters the battlefield tapped unless you sacrifice a monocolored permanent.
: Add or to your mana pool.
Sacrifice Howltooth Flats: Add or to your mana pool.
, Sacrifice Howltooth Flats: Add to your mana pool.
: Add 
or 
to your mana pool. or to your mana pool., Sacrifice Howltooth Flats: Add 
to your mana pool.
