The Caliginous Stones of Frobar were thought to have all been lost at sea in the great storm of 738 GUE, but one was discovered on Discipline Beach by a man (with the alias of "Detective Softly") during the Great Monster Uprising.

Upon discovery, it was addressed G.U.E. Tech with chalk, and mailed to the the Grand Wizard who intended to use it to power a machine capable of creating a Blaine field. Unfortunately, the chalk did not rub off and smudged everything. The only equipment capable of removing the impurity was St. Quakko's Sacred Soap and Towel Set. The relic cleansed the Caliginous Stone, which was then able to be used in the Dex Machine. When the device was put to use, a demon smashed it, warping the Caliginous Stone to Frobar in the impact. While it was still functional, the stone did cause the device to randomly explode. To prevent this, the wizards recalibrated the magical frequencies of all the pieces individually using the Cardinal's Toolbox.

SOURCE(S): Legends of Zork