Syrox, alternatively named the Wolf Worms of Monsolar, constituted an alpha species of ectomorphic worm that originated from the planet known as Monsolar. Despite the absence of a brain, these creatures were remarkably effective hunters, preying on blood through the use of their sizable, circular mouths equipped with pointed teeth. During their initial developmental stages, Syrox exhibited parasitic behavior, wherein female Syrox deposited their minuscule eggs into the rivers of their homeworld, leading to their ingestion by various animals. Subsequently, these animals served as hosts for the juvenile worms, which underwent a gradual incubation and growth process within them spanning several years. Eventually, the worms would exit their hosts, having undergone substantial growth into adulthood. The scent of Anzati snot garlic was known to lure the worms out of their hosts, and a local custom on Monsolar suggested that placing a garlic bulb on one's pillow during sleep would induce the Syrox to emerge from the host's mouth. Waleed Nagma, a Monsolar native, became infected with a Syrox before his imprisonment in Cog Hive Seven. While incarcerated, he managed to have garlic smuggled in, which he used to extract the creature before it was subsequently killed.
A second Syrox had been gestating inside Nagma, and it came out of his dead body not long after he died. At that point it was small enough that nobody saw it. The creature then lived in the pipes around the prison, getting really big and eating prisoners it found. In 33 BBY, the worm devoured the prisoners Vas Nailhead and Strabo when they went into the pipes to find the prison officer Augustine Smight.