Void Block,Void shard and Enchantment in a bottle.

It would be a unique way to set up mob farms. They would spawn at bedrock level and will require a diamond pickaxe to mine. It will take twice as long as obsidian to break and when broken can have a 60% chance of dropping a void shard. When 9 void shards are combined in a crafting grid you will receive the crafted version of the Void block. Place this down and all nearby entities will start to take void damage in a 5x5 block square. Also the void block can not be picked up by silk touch and when you throw anything on it it will disappear. If you put the void shard in your brewing stand with any base potion you will be given a enchantment in a bottle, which when thrown will drop one random enchanted book.