The Swamp Witch was an evil creature living in a tower in the Swamp. Though ordinarily kept mostly under control, the Cataclysm provided ample opportunity for her own sinister schemes to be enacted. She stole the Unicorn Horn from the Unicorn in Daventry, also poisoning a pool in that land. Afterwards, she concocted a venomous poison in her magical cauldron and infected the waters of the Swamp with it as well. She began creating Goblin Tartar with the Unicorn Horn.
The Swamp Witch is a boss monster in King's Quest: Mask of Eternity.