Key to the Underworld

The first time you scry each turn, you may reveal
a nonland card with mana value of X or less from
among cards you've looked at, where X is the
number of cards you've looked at. If you do, you
lose X life, then put it into your hand.
{x}{w}{b}, {t} : Scry X. Activate only as a sorcery
and only if you've lost X or more life this turn.