Aine, Heart of Summer

Aine, Heart of Summer enters tapped unless
you control a mountain or forest.
{t}: Add {r} or {g}.
{2}{r}{g},{t}: Add {2}{r}{r}{g}{g}. Spend this
mana only to cast creature or enchantment spells.

“Enjoy that transient victory, Duchess. Summer comes for you now, and there is no escape.”
-Sulia, Princess of High Noon