The Flood of Mars

Islandwalk usually reads as a static keyword you either turn on with a dual land in your own colors or forget about; here it is the win condition and the engine feeds it. The attack trigger drops a flood counter on a land to make it an Island, which means the same creature that punishes an Island on the battlefield is busy manufacturing one every combat. Left unchecked, it walls off its own evasion problem by converting the defender's manabase into the exact permanent type that lets it through unblocked. The creature-copy half of Water Always Wins is the louder effect (turning a blocker into another copy of a 3/3 that also floods things on attack), but the land-conversion clause is the quieter, nastier half: it is a self-sufficient evasion loop that does not care what colors the opponent plays. Copy-on-attack effects have shown up before as combat tricks or army-in-a-can builders, but pairing the copy with a terrain-changing counter turns a single unblockable body into a spreading condition. The design leans on flavor doing structural work: water spreads, everything it touches becomes water, and the board slowly drowns into a sea of identical horrors marching through Islands of their own making.