Glistening Marsh

Enters the battlefield tapped.
Pay 1 life: Untap Glistening Marsh.
{t}, Return a basic land to your hand: Add twice
the mana that land would have created to your
mana pool.
{2}{t}: Add {u}{g}, {g}{w}, or {w}{u} to your mana
pool.
" The river is said to heal those who are worthy, but
kill those who aren't. I wouldn't take any chances."