Lava Leylines

The Serpent army is attacking the island, aiming to eliminate all of the Islanders. The Serpents tunnel under the island, popping up under damaged land. As the Islanders safety from land is destroyed, water tiles are exposed for them to rain down Lava from their volcano. Islanders drown if the land underneath them is destroyed. Serpents are melted by Lava if they end a turn surrounded by 2 or more Lava tiles - and then harden to become new land.