Ghost Chests that when having fast reaction times rewards you.

So, mineshafts are a bit bland right now, even with all their new addons! Lets change that. Sometimes Ghost Chests will appear, chest minecarts that appear out of nowhere! These contain mineshaft loot tables of course. But with these there is a catch. When they leave the players vision, they disappear. These chests will never be seen again! They will also always contain atleast 1 enchantment book. Thank you for reading! Goodbye.