The Clear Spindle is one of a trio of Precursor artifacts whose mystical links to each other were first sensed by Pkunk psychics. (The other two artifacts being the Aqua Helix and the Rosy Sphere.) The three artifacts were given simple names based on their color and shape. As with other Precursor artifacts, the Spindle's composition and method of operation are unknown, though testing has shown the Spindle to become a superconductor between the temperatures of 18 and 22 degrees C.
The Pkunk were only able to obtain for themselves the Clear Spindle; sensing its power and significance to future history, they were unable to divine anything about its function or internal operation, and therefore kept it for years as a work of art and paperweight due to its unusual luster and near-perfect transparency. Over time they slowly divined more information about the other devices to which the Spindle was mystically linked. This culminated in their guide spirits' compelling them to give the Spindle to the human Captain and guide him in reuniting it with its companion devices, resulting in the reconstruction of the Ultron.