Orb of Dreams

The cruelest tax in Magic is the one that quietly breaks everything that comes after it. Three mana buys a single sweeping rule change: everything enters tapped, not your lands, not your creatures, not the opponent's. The asymmetry is invisible until you build for it. A deck that wants its permanents tapped anyway (because it gates them through other means, or because it simply attacks and never needs the surprise of an untapped blocker) pays almost nothing, while every combo that hinges on a creature being ready the turn it enters, every haste enabler, every freshly fetched land you meant to tap for mana, every flash blocker suddenly chokes. It punishes the decks that treat the battlefield as a tempo resource and leaves alone the decks that play to the long game. The trap is forgetting it cuts your own board too: slam this, then need mana off a land that comes in tapped, and you have fooled yourself. Its closest cousins are the artifacts that rewrite a fundamental assumption of the game and dare you to find the build where the entire cost lands on your opponent's account, not yours. Those rules are read in a sentence and understood over a season; this one took players years to find the shells where a symmetrical-looking clause plays as one-sided.