The Raen sovra, or electrocution worm, was an exotic species of worm first discovered by Dr. Safford Raen on Tenek, in the Mis-Tenek system. These segmented worms had a flexible metallic exoskeleton, and fed off electricity and metal. While they were a vital part of the ecosystem on their own planet, they were a serious threat to technological devices in the greater galaxy.

Raen sovra could sense the flow of electrical currents, allowing them to search for "food." They could also store electrical energy, allowing them to deliver a deadly electric shock if disturbed. As well, their physiology did not require air, and was resistant to extremes of temperature, allowing them to survive indefinitely in the vacuum of space. This made them a serious threat on board a spacecraft or space station, where they could drain energy, eat wiring and other metal components, and disrupt computer processors.

Dr. Raen first became interested in the sovra during his expedition while investigating the vinna trees and their thick, metallic bark. After several of his researchers were electrocuted, he discovered that the sovra living in the vinna roots fed off electrical energies conducted by Tenek's frequent lighting strikes from the trees to the moist soil. Sovra living in the soil fed off this electricity, with millions of the burrowing worms tilling the soil and thus distributing nutrients to the plants of the forest. Aside from the high levels of electrical energy and metallic elements in the system, this symbiote circle was similar to that found on many other planets.

Due to the inherent dangers of the worms, the Mis-Tenek system was blockaded during the Imperial era. Some smugglers continued to land on Tenek, accidentally spreading the sovra with them. While some sovra-infested ships were lost in hyperspace due to damage and energy loss, others managed to make their next destination. This spread the worms from spaceport to spaceport.

The quarantine of the Mis-Tenek system was contested by some zoologists who wanted to study the sovra, especially their mechanism for creating their exoskeletons. Some private interests were willing to pay a substantial sum for a live sovra. The Galactic Empire also collected sovra, hoping to develop a "living armor" technology. One result of this research was a high-powered vibrodagger used by Imperial Intelligence assassins.