Lake of the Opus

{t}: Add {1} to your mana pool.
{t}, Pay 1 life: Add {u} to your mana pool.
{2}{u}{u}: Discard this card from your hand: Counter target spell. You may activate this ability any time you could cast an instant.
From the surface, one could gaze into its depths and see shimmering sapphires lining the bottom of the lake's floor...