Inquisitor's Snare

Two mana for a fog that turns into removal the moment the named colors show up. White pays for unconditional damage prevention on a single attacker or blocker, so the floor is always a clean blank of one creature in combat; the destruction rider collects the kill only if that creature happens to be black or red. That color-keyed clause is what pays for the rate: stalling a green or blue creature is just a one-target fog, while ambushing a black or red threat converts the same two mana into removal that also strips its swing. The instant timing carries the weight here. Held up during the opponent's attack step, it lets you pick the most threatening attacker, prevent its damage, and leave a corpse where the swing was; a blocker the opponent commits to your own attack can be answered the same way, with the destruction landing before the damage step. It belongs to the old tradition of color-pie hosers, the cheap conditional answers white was handed against its philosophical enemies, where the payoff scales directly with how heavily the opponent leans on red and black. Against the wrong deck it is an awkward single-target fog; against the colors it names it is two-mana spot removal with a free combat blank attached. It never pretends to be more than a metagame tool: high and narrow at the ceiling, always serviceable at the floor.