Hidden Oasis

Hidden Oasis enters the battlefield tapped. When Hidden Oasis enters the battlefield if you control another Desert target creature gains Shroud until
end of turn.
{t}: Add {c} to your mana pool.
{t}: Exert Hidden Oasis; Add {g}, {u}, or {1}{w} to
your mana pool and gain 1 life.
Life hidden in the harsh wastelands.