War Barge

The fiction is a transport ship ferrying troops across water, and the rules text follows the metaphor with surprising bite: islandwalk arrives not as a printed creature keyword but as a temporary evasion grant, conditional on the defender controlling an Island, and the moment the Barge is gone, whatever it was carrying drowns. That destruction trigger is what gives the card its teeth and its liability in one motion. The same source that lets your creature slip past blockers kills it outright if the artifact leaves the battlefield before the turn ends, with no regeneration permitted. The design logic is a trade: pay the activation cost for a guaranteed unblocked swing against an Island deck, but accept that an opponent who destroys the Barge after the ability resolves turns your own attacker into a casualty. This is the kind of high-friction, double-edged effect The Dark traded in, when "evasion" still meant exploiting the opposing manabase and an artifact could carry a curse as easily as a blessing. The islandwalk grant only matters against blue or other Island-controlling decks, which makes the whole engine a narrow answer to a narrow problem: an artifact that solves combat math against one color and does nothing against the other four.