or 2 life.)Dismember gives black decks a flexible removal spell whose mana payment can be reduced by spending life. It gives a target creature -5/-5 until end of turn, often removing a threat for just one mana and four life. Paying some or all of the black mana instead preserves life when the game has become a race or your deck already uses life for other costs.
The toughness reduction is useful against indestructible creatures if it brings their toughness to zero or less. It also changes combat math against larger creatures that survive, allowing a smaller blocker or another damage source to finish the job. This gives Dismember applications beyond simply answering a creature with five toughness on an otherwise empty battlefield.
Black midrange and combo decks can keep a low-cost answer available while developing their own engines. A single untapped land may be enough to represent removal, making it easier to protect a turn without leaving several mana unused. The four-life option is less attractive when multiple opponents can attack you or when paying that life removes the buffer needed for Necropotence or other abilities.
Choose the payment according to the position rather than defaulting to the cheapest mana cost. Dismember still targets, so hexproof and other targeting restrictions matter. It also provides only a temporary reduction, meaning a large creature that remains alive returns to its normal size at the end of the turn unless another effect changes that outcome.
