In ancient times the Drow revered the Dargrith as ascended ones, and was a ritual given unto dying Kings and Queens in what was thought as a process that reserved them. This tradition eventually gave out after one such Queen ate her entire court, but some Drow still hold reverence over these creatures. Much to their own dismay at times.
In reality the Dargrith is a parasite, one born initially from a single worm that if ingested will begin to grow within the digestive system of its host, until their guts have expanded and the parasite bursts upward, effectively bisecting and killing its host while retaining control of the remaining nervous system to command its legs and any other remaining limbs. Once it has reached this stage it is known as the “Ascended” and begins its mature lifecycle of endless hunger. As each creature is devoured by the Dargrith, its mass grows, but so too does its hunger, exponentially.
At some point if left unchecked a Dargrith will grow so large that it can no longer support itself, as its hunger is unquenchable. It is here that the Dargrith enters the final stage of its lifecycle as it begins breaking itself down, eating itself to stave off hunger while doing irreparable damage to its own body. In this stage the Dargrith will begin excreting thousands of worms, its offspring to continue the cycle, though most will die before they get the chance. Here in the final throes the Dargrith will complete the cycle after it consumes the last few limbs and bodies that remain in its mass, and it dies. Thus the best way to ensure no cycle continues is killing the creature before it can reach such a gargantuan size, using ice to break away its frozen bodies.