The phantom pickaxe would be a very useful tool. It would be crafted from 2 blaze rods and 3 phantom membranes. The phantom pickaxe would have the same mining speed as gold tools, but it would be indestructible. However, to keep things balanced, it would not be able to mine obsidian or diamond ore. The phantom pickaxe would be able to receive any enchantments a pickaxe can have. If you die, the pickaxe will instantly disappear. The phantom pickaxe would essentially be used when you are strip mining or removing lots of land. The pickaxe would not be too overpowered because it disappears upon death, it cannot mine two essential blocks, so diamond tools would still be required, and it would be hard to get because of the materials it requires.