(Goblin Karst isn't a spell.)
Goblin Karst enters the battlefield tapped unless you pay .
, : Scry 2.
: Add or to your mana pool.
: Add to your mana pool. Put Goblin Karst on top of your library.
.
, 
: Scry 2.: Add 
or 
to your mana pool.: Add to your mana pool. Put Goblin Karst on top of your library.
