Diviner's Lockbox

A gamble dressed as an artifact. Four mana buys you nothing on entry; the payoff sits behind a name-the-card guessing game, activated at sorcery speed for one more mana, with a hit sacrificing the box to draw three. The design is a deliberate exercise in variance-as-cost: instead of paying life or discarding to draw, you pay uncertainty, and the "choose a card name" clause turns your knowledge of your own deck into the resource that unlocks it. That framing is the whole trick. Because the check is against a specific name and not a card type, the odds only improve when your library actually runs multiples of the same name: a deck leaning on four-ofs or clogged with identical basics turns the guess into something closer to a plan, while a toolbox of singletons leaves you flipping a coin on turns you have nothing better to do. The reveal-then-check structure is the mercy in the design: a miss costs you the mana and the activation but never the named card, so failure is slow rather than punishing. And the sacrifice clause makes this a one-shot regardless: even a hit spends the artifact, so the box is a delayed, conditional draw spell rather than a repeatable engine. It belongs with the colorless card advantage that asks you to do arithmetic on your own list before it pays out, closer in spirit to library manipulation than to a flat draw rock.