Wither bones are created from the bones of a dragon that became a ghost dragon. If the bones are broken they cause anything within 5' to wither and decay. This causes death to plants and to animals of less than 1HD. Other creatures must make a Fortitude check (DC17) or age 1-3 years. A failed save requires another Fortitude check (DC15) or the creature is cursed to become a ghost when they die. This curse can be removed by a priest of 11th level or more.
Wither Bones are used in making arrow, javelin and spear tips. This leads to discoloration, and eventual corrosion, of the surrounding metal. Wither Bones continuously release ghostly streams of white smoke.
As a result of the dangers of handling Wither Bone, it is normally only used by undead, Aggorath or Muneyd'vith. Both of these latter dragon-blood races are unaffected by the bone's baleful energy.