No Quarter

A combat-math punisher dressed as an enchantment, and the symmetry is the whole point. Most blocking rewards or penalties care about who wins the fight; this one cares only about the power gap, and it cuts both ways without prejudice. Block a bigger attacker with a smaller creature and your blocker dies before damage is even assigned; send a small attacker into a larger blocker and the attacker dies the same way. The destruction triggers on the act of blocking itself, not on combat damage, so toughness and first strike never enter the equation: a 1/1 that blocks a 2/2 is gone regardless of how the fight would have resolved. That turns the board into a standoff where the only safe interactions are even-or-greater trades, which is a strange and specific kind of pressure. Note that the effect reaches only blocked creatures, so a smaller attacker is perfectly safe as long as nobody blocks it; the danger is in committing a creature to combat against something larger, on either side of the board. It hands the initiative to whoever fields the bigger bodies, because a defender can no longer chump-block a fattie and a small creature can no longer profitably trade up. The design belongs to a Tempest-era appetite for combat-warping enchantments that rewrote a rule everyone took for granted rather than adding raw stats. It is less a removal engine than a tax on inefficient combat, and the player who internalized the power-gap rule first won most of the fights it created.