Wistful Wild

Wistful Wild enters the battlefield tapped.
{t}: Add {b} or {g} to your mana pool.
{3}{b}{g}, {t}: Look at the top ten cards of your library. You may put any number of Groink or Grub-dog creature cards from among them onto the battlefield. Put the rest on the bottom of your library in a random order. As an additional cost to cast this ability, sacrifice a land.