Pact Weapon

As long as Pact Weapon is attached to a creature,
you don't lose the game for having 0 or less life.
Whenever equipped creature attacks, draw a
card and reveal it. The creature gets
+{x}/+{x} until end of turn and you lose {x} life,
where {x} is that card's mana value.
Equip - Discard a card.