New Nether Biome: Cursed Cave

This new Nether biome would be quite difficult to get through, and easy to get lost in (not unlike the netherwart forests) but it would be black themed with obsidian and lots and lots of stalactites and stalagmites. Wither skeletons would live here, as well as maybe some new mobs. It would be quite dark, and the fog would be black and make it difficult to see far away.