Witherstone

Helps players mine blocks with a catch.

When placed, the Witherstone emits a decay aura in a certain radius around it. Any blocks within this radius gradually deteriorate over time. The decayed blocks turn into crumbling versions (some blocks should be immune to this). If left to decay forever the blocks will disappear, but if the fuel is timed to run out correctly the blocks should stay in a frozen crumbled state (unless the wither stone is destroyed) with a greatly reduced mining time. To keep it simple most blocks should be clumped up into certain specific deterioration times e.g. stones, soils, woods, etc. To allow for use in more than just mining.

I think this idea could potentially be a very, very powerful game mechanic, as it could;

• speed up the mining time in caves (particularly deepslate mining) 
• Add controlled decay as a build feature 
• Have use in various aspects of gameplay including building, landscaping and even custom map creation.

Ways I think this mechanic should be constrained;

• The decay aura should be disarm-able in some way to avoid griefing. (Maybe beacon disables it?)

• The witherstones should not spawn naturally in the world as it could be jarring to new players. They should be craftable.
• Should have a crafting recipe or special table of some kind to craft that does not lean too heavily in favour of redstoning or automation. (Advanced redstoning is a bit too powerful in my opinion and has largely broken the in-game economy between redstoners and non-redstoners)