Enchanted Boulderfeild

Enchanted Boulderfield enters the battlefield tapped.
At the beggining of your upkeep, summon a 0/2 Rock and a 1/1 squirrel.
{x}{w}{r}{g}, {ut}: Create X 1/1 squirrel.
{x}{w}{r}{g}, {ut}: Create X 0/2 rocks.
{t}: Add {c} to your mana pool. Use this ability only once per turn.