Pact Weapon

The devil's bargain rendered as an Equipment: strap it to a creature and zero life stops being a loss condition, which turns your life total from a countdown into a spendable resource. The attack trigger is the engine, and it is deliberately not a clean cantrip. When the equipped creature swings, you draw the card and reveal it, so you keep the card as real advantage, but the reveal fixes X at that card's mana value: the creature gets +X/+X for the turn and you pay X life. A land off the top is a whiff and a free +0/+0; a big spell is a huge swing and a huge bill. The two abilities cover each other only halfway. The no-lose clause insulates you from the drain the sword inflicts on itself, but nothing here stops an opponent from destroying the Equipment mid-combat or draining you the instant it's gone, at which point every point you overspent comes due all at once. The discard equip cost keeps the reattachment tax high, so this isn't a blade you casually shuffle between blockers; it's built for one dedicated carrier in a deck willing to treat its own life bar as fuel. The Faustian catch is stitched into the timing: the protection lasts exactly as long as the weapon stays on the body, and the moment it comes off, the debt is real.