Mercury Cell

Mercury is a liquid metal at room temperature and room pressure. As such, it cannot be contained without a container. It is fairly hard to get, as it requires the Lesser Centrifuge and at least two Lava Cells. It takes four of the Depleted variety to create a fully-filled cell. If you craft 1 Mercury Cell (fully filled) with a bucket, you get a Mercury Bucket and an Empty Cell (the Empty Cell is dropped into your inventory). Then, Mercury can be placed as a liquid. It flows as fast as lava but with the maximum spreading range of water. Most entities float in Mercury, as it is a very dense liquid. The recipe for a Mercury Bucket can also be done with 4 Depleted Mercury Cells instead of 1 fully-filled cell, and it drops 4 Empty Cells into your inventory. As a liquid, it has a blast resistance of 1250, both as a source and as a flowing block, enabling it to survive most explosions, even a Nuke. It also nullifies the damage to blocks when an explosive ends up in it. Explosive entities, like lit TNT, float in it, but they stay about 7/8 below the Mercury line to enable its nullifying. Mercury may be able to be crafted into a Thermometer and maybe some Potions.