Rage Extractor

The trigger keys off a symbol, not a payment: it watches for the in a spell's mana cost and fires whether you satisfied that cost with mana or with life. The reward is the same either way, and it lands wherever you point it (any target, full mana value, no discount applied to the damage). That decoupling is the whole design. Phyrexian mana exists to let you cast a spell cheaper than its printed value, but this artifact deals damage equal to the printed value regardless of how little you actually paid, turning every spell on the board into a burn rider that scales with the cost you dodged rather than the cost you paid. A heavy Phyrexian-mana creature you slammed off life still throws its full mana value at a face or a blocker. That makes this a build-around chasing critical mass of across a list rather than a single combo line: load up on Phyrexian-mana threats and removal and the deck quietly becomes a burn engine that happens to be deploying creatures on the side. The in its own cost is the wink, letting you assemble the engine off life when red is short, and it embodies the era's central wager: life is just another resource to spend cheaply, and this artifact pays you for spending it.