Laurel Caverns (Cave of Souls)

As Laurel Caverns enters, choose a creature type.
{t}: Add {c}.
{t}: Add one mana of any color. Spend only to cast a creature of the chosen type, and that spell can’t be countered.

"Laurel Caverns is a large natural calcareous sandstone cave located 50 miles south of Pittsburgh. Because of its size, Laurel Caverns is also the largest natural bat hibernaculum in the northeastern United States."