Merfolk Assassin

A hyper-conditional answer that reads less like a card and more like a punchline: an assassin that can only kill creatures already wearing islandwalk. The design belongs to a specific early-Magic instinct, the idea that an ability should be priced near zero precisely because the prerequisite does most of the work. The tap cost is free because the targeting clause is the real expense: the only creatures this can destroy are those that currently have islandwalk, a keyword that exists to be unblockable across an opponent's Islands. The kill itself is clean (it destroys, it does not stun or bounce) and it fires at instant speed, since nothing on the card restricts the tap, so the assassin can answer the islandwalker the moment it threatens, before combat damage rather than after. Note the irony baked into the restriction: the creatures this answers are precisely the ones your blockers cannot stop, because islandwalk lets them slip past anything, yet the assassin reaches them by aiming at the keyword rather than the combat. It reads as deliberate color-pie policing aimed at the islandwalk-as-evasion theme that ran through Magic's earliest sets, an answer-to-a-single-problem design back when the game still printed cards whose entire reason for existing was to embarrass one keyword. The problem it answers can simply decline to show up, which is why this kind of single-target reactive design largely vanished from later sets.