Fog Patch

Most fog effects intercept the combat damage step and replace the damage event with nothing: the attack lands but does no harm. This one works a step earlier, in the declare blockers step, and wins the assignment outright. The window is razor-thin by design, opening only after attackers are committed and closing before damage assigns, and what it does in that window is the inversion of evasion. Flying, shadow, the broad "can't be blocked" stamp: none of it matters, because the spell does not interact with how a creature got through. It simply declares the attackers blocked, retroactively, by nothing at all. A creature that is blocked but has no blocker deals no combat damage, and that is the loophole. It is also why the reminder text exists: the designers knew the natural reading ("blocked by what?") was the whole point. The one evasion ability it does not beat is trample, the exact case where a blocked creature with no blocker still tramples its full damage to the defending player; the card is famously dead against it. The real edge over an ordinary damage-prevention fog is narrower than it looks. Both keep the affected attackers from dealing combat damage to the defending player. What this one additionally cuts off are triggers that key on attacking unblocked: ninjutsu-style abilities that a prevention shield leaves perfectly intact, because under a standard fog those creatures are still unblocked. The cost of all that precision is the timing lock: surrender the freedom to cast on a whim, and in return you rewrite the block rather than erase the damage after the fact.