Foam stalkers are elemental water creatures. On Marapur they emerge from the spray of waterfalls cascading down from the mountains. Since they cannot survive on land for long, they quickly retreat below sea level after their emergence and thus populate the reef caves beneath and around Marapur. Because of their elemental bodies, it is often difficult to distinguish them from the water around them. As they roam the reefs, they often capture coral branches, flotsam, pearls or small fish with their swirling bodies. These objects can then be seen swirling around in their watery shapes.