Outpost Siege
The choice this enchantment forces on entry is the whole design: it splits one slot into two effects that almost never want to do the same job. Khans is the long-game half, a four-mana advantage engine that converts your upkeep into an extra card each turn at the cost of a finite window: exile it, play it this turn or lose it, which makes lands and cheap spells the cleanest payoff and expensive cards a gamble. Dragons is the closing half, a Goblin Bombardment that triggers off any creature leaving the battlefield, not just dying, so tokens, sacrifice fodder, even creatures you blink or bounce all feed a steady drip of reach. Both faces read as full effects rather than a downgrade glued to a stronger one, which is why the same physical card can pull duty as an inevitability engine in one deck and a damage outlet in another. The permanence is where the friction lives: you pick before the game has shown its shape, so the decision rewards reading your own deck rather than the board in front of you. Grindy attrition shells almost always want Khans; board-presence aggro and sacrifice builds want the ping. Modal-on-entry enchantments like this one live or die on whether both halves justify the mana, and here neither one is filler.
