Envenomation

A curious property of the venom of the Blueback Marauder is that it prevents the decay of living matter. The spider uses this to preserve the small creatures it hunts, so as to build up a supply of food for when the region's notoriously unpredictable weather renders hunting unfeasible. Though ingesting material thus preserved will cause stomach-illness is most any other creature, Kantirini schloars have devised a means by which harvested venom may be used to preserve nearly any organic material[...]

— from Beasts of the Horn of Pelekath

Utility

The worst mistake a person could make is to eat something which has been preserved through envenomation. Though it does prevent decay, the venom itself will make any creature other than a blueback marauder grievously ill—which would not be lethal, but would be thoroughly unpleasant.
The chief use of envenomation is scholarly, preserving samples of unknown species in the wild—be it flora or fauna—so that they might be studied in detail in a more hospitable environment.

Access & Availability

Access to properly treated blueback marauder venom is limited. The Kantirini Palace of Sight carefully regulates and restricts the knowledge of how to treat raw blueback marauder venom to that it might be used in envenomation. Scholars belonging to the Palace of Sight, who are in good standing, have a relatively easy time acquiring envenomation materials, whereas foreign scholars may purchase the materials—if both they and their institutions are looked on favorably by the Palace of Sight—for an exorbitant price.

Complexity

For those with access to properly treated blueback marauder venom, the process is as simple as submerging the desired subject into it. Producing such venom from scratch is considerably more complicated, requiring an iron vessel, carefully ground lenses, and the means to harvest the venom in the first place.

Discovery

Scholars from the Celestial Regency of Kantirin's foremost house of learning, the Palace of Sight, were on an expedition to the Horn of Pelekath, when they observed that the Blueback Marauder—a type of very large spider—would gather store many of the small mammals and lizards it hunts, rather eating them right away. Taking a number of specimens back to Kantirin, they found that the spider's venom not only killed the creatures, but acted to ward off decay for a protracted period of time.
From there, the scholars developed a means of treating and altering the venom, so as to be able to utilize this effect for themselves, a process which has come to be known as envenomation.