Arms Race

A rental engine for artifacts, built to answer a specific tension: dropping expensive artifacts into play ahead of their cost is powerful, but a permanent, unconditional version of that effect would push every colossus and doom-cannon past the ceiling. So the payment is structured as attrition. Four mana per activation puts an artifact from hand onto the battlefield with haste, then makes you sacrifice it at the next end step. What you buy is a single turn's worth of a big artifact: an attack, an activated ability, an enters-the-battlefield trigger, then it goes to the graveyard. That end-step sacrifice is the whole balancing act, because every giant construct you cheat out has to earn its cost in one window rather than sticking around to accumulate value. And because the clause sacrifices rather than destroys, indestructibility offers no escape hatch: the artifact leaves regardless of what would normally protect it. The design rewards artifacts whose payoff is front-loaded (a swing that closes the game, a fabricate or amass trigger, a Myr Battlesphere's token dump) and quietly ignores anything you would want to keep, since the thing never returns to hand. It reads as an aggressive, temporary version of the reanimator fantasy applied to metal instead of monsters, trading the graveyard requirement for a per-turn mana tax and the survival of the thing you are conjuring out. The sacrifice is not a drawback bolted on; it is the price that lets a repeatable four-mana enabler exist at all.