Wormfang Turtle

Half the Nightmare cycle runs on the same wager: take a discounted body, then pay for it by exiling one of your own permanents. The tax here lands on the manabase. Exiling a land the moment the Turtle resolves is a real tempo hit (you set yourself back a drop on the turn it arrives), and the recovery clause is built to look helpful while doing very little: the land returns only when the creature leaves the battlefield, which means the most natural way to free your mana is to lose your blocker. The design tension is that the 2/4 and the rate are perfectly reasonable on their own, so the cost is structured to make you unhappy precisely when nothing bad happens to the Turtle. Where it gets clever is the framing of "leaves the battlefield" as the payoff rather than the loss. Bounce it, sacrifice it, or flicker it, and the exiled land comes back at instant speed, turning the entry penalty into a deferred mana payment you can settle on demand. Note that this restores parity rather than generating advantage: getting your own land back is breaking even, not a two-for-one, and removal that kills the Turtle simply hands your land back as it dies. The card carries no self-bounce of its own, so the whole engine depends on outside enablers. That dependency is why the Nightmares survive as a curiosity: they reward decks already manufacturing their own departure triggers, where the entry cost is paper and the return is the plan.