Underground Conduit

Crafting recipe is similar to the normal conduit, with Soul of the Earth in the center (dropped by Warden) surrounded by amethyst crystals. Benefits could include things such as night vision, haste 1, and slow falling. The conduit could also make lava semi-invisible, enough so you could still clearly see the lava but could also see the blocks under it. It would also kill mobs similar to the underwater conduit, and possibly stop them from spawning. The blocks required to surround the conduit to activate it would be Copper Blocks.

These are all tentative and could be changed, however, I still think it would be a good idea to add some form of an underground conduit and also have the warden drop something useful.