Sweeping Poisonous Gas

Lands you control have "{1}, {t}: Target player
gains 10 life and gets a poison counter." If an
opponent has 50 or more life, you lose the game.
Circular Tap (You may infinitely tap this
permanent, each time rotating it 90 degrees. If it is
directly upwards, it is untapped.)
{t} or {ut}: Add {c}. Activate this ability only twice
each turn.
{t} or {ut}: Add one mana of any color. You lose
2 life. You get a poison counter.