Spiked Pit Trap

The dice-roll finish is the whole point: a colorless removal artifact that costs six mana across its life (one to deploy, five to fire) and asks you to gamble on the payout rather than the effect. The 5 damage lands regardless of the roll, so this is not a risk of missing your kill; it is a lottery on whether you get paid back. Roll a 10 or better and the sacrificed artifact spits out a Treasure, refunding a chunk of that activation cost and letting the removal partially rebuild your board tempo. Roll single digits and you simply ate a slow, expensive shot. Both halves run at instant speed: flash lets you deploy on an empty turn without telegraphing anything, and the activation carries no timing restriction, so you can fire it mid-combat, in response to a pump spell, or on the opponent's upkeep to reset initiative. Stacking instant-speed deployment onto an instant-speed activation is unusual for removal at this cost; most colorless answers this reliable live in slower shells and demand you show your hand a turn early. It belongs to the school of design that grafted twenty-sided variance onto a card type that historically prized certainty, and the Treasure upside is the sweetener that let designers accept a swingy outcome on an effect that would otherwise want to be predictable.