Dragon Roost

The pitch is repeatability with no expiration date: pay six to land the enchantment, then funnel seven mana per turn into 5/5 fliers until the game ends. This is a mana sink in the oldest sense, converting surplus lands a slow deck would otherwise waste into a stream of bodies, and where some build-around enchantments trade mana for cards, this one buys raw inevitability. A control deck that survives to the late game wins not by drawing a finisher but by untapping with this in play and seven mana untapped. The cost structure keeps the engine from arriving early: on a clean curve with no acceleration, the first Dragon cannot land before turn seven, and the token itself is generic to the point of austerity, a vanilla flier with no death trigger and no rider. The real wrinkle is where the threat lives. A deck packing only creature removal cannot touch the engine: the enchantment sits on the battlefield and keeps producing no matter how many Dragons trade away, while each token is an ordinary flier any reach or flying blocker can answer. It is not unkillable (enchantment removal handles it cleanly, and it can be countered before it resolves), but against an opponent who left enchantment answers off the list, it becomes a factory whose product is expendable and whose machinery is not.