Vault of the Astral Keeper

{t}: Add {c} to your mana pool.
{1}, {t}: Add one mana of any color to your mana pool.
{9}: Vault of the Astral Keeper becomes Khumbasa, a legendary 6/6 colorless Avatar artifact creature with indestructible, flying, trample, and vigilance until end of turn. It's still a land.