Krosan Constrictor

Every line of this design points at a single opponent. Swampwalk turns the 2/2 body into an unblockable clock the moment the defending player is on Swamps, while the tap ability shaves two power off a black creature, taking the teeth out of whatever they mean to attack with. Both halves depend on a black opponent: one slips past their lands, the other dulls their offense. This is hatebear design from an era when hate was printed as a creature you actually cast and tapped, rather than folded into a sideboard answer or stapled onto a triggered ability that fires regardless of matchup. The narrowness is what that focus costs. Against any deck not running black, both abilities go dead at once: the landwalk has nothing to evade, and the tap effect has no legal target, leaving a four-mana body that does almost nothing. That is exactly why this kind of mono-matchup landwalker faded from later design. The newer convention puts the hate on a body that still pulls its weight against everyone, or ties it to an effect that triggers no matter who is across the table. Krosan Constrictor belongs to the older school: built to swing one matchup hard and to sit inert in every other.