"Dead Lava Zone"
Would replace a chunk of the northeast Crash Zone bordering the Bulb Zone.
The water here is dark grayish at surface level and remains so until deep down., where the lava is the only light. This biome's "surface layer at about 180m-350m has small lava rivers and geysers, and is incredibly uneven and shattered. The deepest parts are about 350 meters down, after which the cave versions starts. These caves actually lead to the Inactive lava zone, and are rich in Shale and Rubies. Both the caves and surface have lava hardened into strange formations, and when the players gets close to the surface, they start to take weak damage from the heat of residual lava.
Fauna/Flora: Shallow-water forms of Inactive Lava Zone creatures, Bonesharks, "Lava Eels", and in the caves "Ember Leviathans", which act like juvenile Ghost leviathans but smaller and slowly stalk the player.