Marsh Gas
A combat trick built backwards: instead of pumping your blocker, it shrinks every attacker at once, shaving two power off the board for a single black mana. The symmetry is the balancing friction. A one-sided power reduction would be too strong for the era, so it hits your own creatures too, casting this firmly as a defender's tool rather than an aggressor's. The math rewards the player taking the swing rather than throwing it: any creature with two power or less becomes harmless in combat without ever needing to assign damage, and a wide attack from a board of small creatures can be blanked outright. The -0 to toughness is the tell. This is not a sweeper and never threatens to kill anything; it only rewrites the damage step, which is the reason it has to be cast at instant speed to matter. The window is narrow and precise: hold it for the declare-attackers step, let the opponent commit, then collapse their damage output before blocks resolve. Black rarely gets to interact with combat from the power axis this cleanly, since the color's usual answer to creatures is just to kill them; this is one of the rare instances where black plays the temporary, reactive role white and blue more often own.
