Blackveil Sting

The Blackveil is a small species of jellyfish native to the Tescaries. Touching one of these jellyfish with bare skin will expose you to the Blackveil's venom, causing severe itching, reddening of the skin, and in high concentrations potentially lethal toxic shock. The skin may break out in hives, and begin to swell as the blackveil's venom works its way into the tissues.
The Tescarana are very familiar with Blackveils, and their sting is a well-known threat for anyone who seeks to harvest snails from the shallows around the isles. The dye-producing snails and the toxic jellyfish share much of their range. Though some have attempted to weaponize the jellyfish, the creature's venom has thus far been impossible to extract, and in any case the jellyfish dies within minutes of being removed from the sea. As a result, the Blackveil's sting is simply a pest for those who work in the shallows.

Prevention

To avoid stings, snail harvesters often hunt for snail with gloves and a net on a pole-and-hoop construction. Experienced snail harvesters know to prod any dark waters with poles to dislodge any jellyfish. Knowing the creatures will rather swim away from threats than sting them, the blackveil should only sting if surprised. Nevertheless, stings cannot always be avoided. In case of a blackveil sting, the Tescarana know to scrape the venom off the skin with the back of a knife or treat the sting with vinegar. Preferably, both will be done.
In any case, blackveil sting runs its course quickly. If the affected goes into shock, death within minutes or hours is likely. In most cases, the sting is fought off by the body especially when proper countermeasures are taken to prevent most of the venom from affecting the body. In such cases, the sting will remain itchy for less than a day, but will have no further effect.