Developed to originally "transport" creatures from one place to another... it turned into more. When you equip a Diamond in your hand, the first time you strike a creature (any Bukkit.Creature), it changes the Diamond to a SoulStone specific to the Creature type, with a randomized number of "Total Points". You kill enough creatures, and it "fills up".
When a stone "fills up", it will either turn into a stack of SpawnEggs (count related to number of kills/points) for that creature type, or it has a chance to turn into a "Soul Pickaxe" with a randomized number of Points (again, related to the number of kills/points).
If you go to any grouping of connected Stone blocks, and place a DiamondBlock on it, and hit the diamond block with the Soul Pickaxe, it will generate into the stone, a network of bricks of varying ores, one per point on the Soul Pickaxe. If it can use all of the points, the Soul Pickaxe becomes a "Soulless Pickaxe" (still usable as a Diamond Pickaxe). If not all points are used, it will be re-usable, with less points. Of course, each use requires a DiamondBlock that gets consumed by the Soul Pickaxe.
I am working to "balance" the default "randomness" in the configuration, so that the amount of effort in generating Soul Pickaxes balances with the amount of ore that you receive from doing so. Seems over-powerful, but it DOES require 10 diamonds to attempt the first time, and probably more, since sometimes all you get is eggs.
Some interesting side-thoughts... on a "FlatWorld" (no ore, limited stone), this would be a way to develop/generate ores. Also works if a world is primarily mined-out. I am working on a "Sphere World" plugin (World-Generator), that creates large spheres in the sky, but the resources can be limited... this becomes another interesting solution to that problem, as well. It also solves some of the "How do you transport Villagers" issue, by giving a Survival-based method for acquiring Villager SpawnEggs.
Have fun, give me feedback, and report bugs!