Crown of Doom

A hot potato made literal. The Crown punishes whoever holds it by turning every attacker pointed at that player (or a planeswalker they control) into a +2/+0 threat, then hands you the means to pass the liability across the table for two mana. The design pressure runs entirely on social momentum: the wearer wants it gone, and the activation is cheap enough that it rarely stays put, but the timing restriction (only on your own turn) means you cannot dump it the instant combat threatens you. You have to plan the handoff a full rotation ahead. That makes it a deal-making artifact in the truest multiplayer sense, where the buff becomes a bargaining chip rather than a board-state problem. The asymmetry is what keeps it circulating: the +2/+0 only helps creatures attacking the current holder, so the Crown is a danger to its wearer and never to the table at large. And the malice cuts both ways. Because the trigger cares about the artifact's current controller rather than its owner, once you give it away your own attackers collect the bonus when they swing at whoever now holds it, turning a defensive nuisance into a personal offensive buff. It belongs to a small family of artifacts built to be handed off as a weapon, and it is among the purest of them: no board impact on its own, just a portable accusation that someone is about to get hit harder than they would like.