Shield Sphere

A free blocker that pays for itself in installments. The zero cost is the whole pitch: it asks nothing of your mana and gives back a 0/6 wall, but the design refuses to let that be permanent. Each block shaves a point of toughness off the body, so the wall is really a stack of six chump-blocks that happens to share a card slot. That structure is the balance lever. A static 0/6 for free would be an absurd defensive floor, the kind of thing that warps early combat math indefinitely; the -0/-1 counter per block converts it into a depleting resource, generous in the first few turns and worthless by the sixth. It absorbs aggression without trading away cards or tempo, but it cannot hold a board forever, and an opponent who keeps swinging will eventually exhaust it through sheer repetition. The free artifact body matters beyond combat: it is a creature you can deploy without spending mana, which feeds anything that counts artifacts, anything that wants bodies on the battlefield to sacrifice or convoke or animate, all at no cost to your turn. That is the design tension the card lives in: it is barely a creature in any aggressive sense, but it is a free permanent with a printed toughness of six, and the counter mechanic is what keeps "free 0/6 wall" from being a sentence Wizards had to ban.