Panharmonicon

The doubler that taught a generation of players to think in triggers instead of bodies. Its restriction is precise and easy to misread under pressure: it multiplies triggered abilities caused by an artifact or creature entering, and only for permanents you control. That last clause is broader than it looks, because the entering permanent is itself yours the instant it hits the battlefield, so its own enter trigger fires twice just as reliably as any other trigger it sets off on your side of the board. What it does not touch is everything outside that window: no cast triggers, no attack or death triggers, nothing for a card entering that is neither artifact nor creature. Within that window it is brutal, because enter-the-battlefield triggers are where modern Magic stores most of its incidental value: every drain, every scry, every token, every "draw a card" stapled to a creature suddenly fires twice. The card reframes what a permanent is worth. A simple value creature with an enter trigger becomes a payload; a one-time blink becomes a two-for-one engine; a sacrifice loop with any enter trigger attached starts generating absurd math with no additional pieces. It loops nothing on its own and asks for nothing but the right kinds of triggers around it, which set the template for a whole family of narrower doublers that each pick a single trigger type to multiply. This is the broad, generous version, the one that says whatever you were already doing with creatures and artifacts entering, do it twice, and leaves the deckbuilder to supply the rest.