Troll of Khazad-dûm

The two halves of this card answer different problems in a black deck, and the design is honest about the fact that you rarely want both. Early, it is a fetch: swampcycling for one mana turns a dead six-drop into a land, smoothing draws and thinning toward your color exactly when a beefy creature would clog the hand. Late, when the mana is there and the board matters, it is a 6/5 that demands three blockers to stop. That evasion clause is the interesting part: it is not menace (which asks for two) but a stricter tax that most midrange boards simply cannot pay without ganging up and losing the trade math. Splitting a creature into a cycling half and a payoff half is an old lever, the modern landcycling designs that let a fatty double as a land, and this one tunes both ends carefully. The cycling cost is cheap enough to make the card near-inclusion-free in any deck running Swamps, and the body is threatening enough that keeping it is a real choice rather than a consolation. The friction is that the cycled half never puts the Troll on the battlefield; you are trading your finisher for fixing, and the card trusts you to know which game you are in.