The Chain Veil

Loyalty abilities live under a single governing rule: one activation per planeswalker per turn, at sorcery speed, paid in loyalty rather than mana. This artifact exists to break exactly that rule, granting every planeswalker you control a fresh activation for and a tap. With one walker that is a modest second tick; with several, and crucially with a way to untap the artifact, it becomes an engine that fires loyalty abilities and ultimates in a loop, generating mana to fund the next untap and clearing the board through repeated minus activations. The end-step life-loss clause is the closest thing to a leash, a small bleed on any turn you don't activate a walker that nudges you to keep firing rather than sit on the card; it was never built to restrain a deck assembling the loop on purpose. What makes the design worth studying is how narrow the hook is: it does literally nothing without planeswalkers, very little with one, then scales past every reasonable curve the moment the count climbs and an untap effect enters the picture. The floor is unplayable, the ceiling is an arbitrarily large chain of activations, and there is almost nothing in between. That binary is precisely why it became the namesake of an entire superfriends combo lineage rather than a fair-deck staple: a card that asks you to build the whole deck around unlocking it, and rewards you with a win when you do.