HEROES OF IMPILTUR
A cataclysmic event which happened nearly a hundred years ago (1385 DR – The Year of Blue Fire) when Mystra, goddess of magic, was killed. Wild Magic ran rampant throughout the cosmos (often manifesting as blue fire) and rearranged the face of the planet.
Those creatures that survived exposure to the spellfire were often horribly mutated and referred to as Plaguechanged or Spellscarred. Some form of manifestation of blue fire almost always accompanies a creature that is spellscarred. In Faerun the spellfire was true chaos and affected each individual that it touched differently; turning one man into a monster while granting the man next to him unnatural long life. In Kara-Tur, while still chaotic, the changes were often more localized such as turning an entire village and its occupants into solid gold.