Smoldering Marsh is a land card featured in the Zendikar Expeditions set of Magic: The Gathering, categorized as an Unknown rarity. It offers strategic value by entering the battlefield tapped unless the player controls a Swamp or Mountain, providing both black and red mana. Currently, it holds a market value of $18.40, reflecting its desirability among collectors and players alike, particularly for those building multicolored decks.