This mod adds Withered Bones, Withered Bone Meal, Withered Bone Blocks, and a Potion of Decay! Withered mobs no longer drop regular Bones and only drop Withered Bones (This can be disabled in the config).
I have this small overpowered issue with the withering enchantment. I use a mod called DualWielding which lets me have tools/weapons in the off-hand. The weapons with the withering Enchantement in the off-hand also gives the withering effect on the main hand punch and shooting with bow/crossbow without the enchantment at all. If you don't want to fix this, fine by me. I didn't test it if it also works without the DualWielding mod.