Evolving Cavern

{t}: Add {c}.
{t}, Sacrifice Evolving Cavern: Reveal cards from
the top of your library until you reveal a land card.
Put that card onto the battlefield tapped, then
shuffle. Add one mana of any color.
Towering crystal beams burst from the cave's shifting
walls. As these hulking structures converged at the
center, the entire grotto was bathed in light.