Stops mobs from burning in the daylight (This can be disabled in the config) and allows hostile mobs to spawn during the day (This is disabled by default and can be enabled in the config).
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).