Spirit spider

Various species of giant spider can be found in nearly any environment where there is a food source. Driven to survive, these incredible arachnids adapt to their surroundings in the most incredible ways.
Taking up residence in sub-zero forests, the Spirit spider is one such example.

Since insects are scarce among the ice, the Spirit spiders have evolved to be nearly two feet in length when fully grown - a suitable size to take on larger mammals for sustenance. These arachnids boast juicy, fat limbs and are covered in dense hair of mottled white and brown to blend into its wintry home and retain body heat. A duo of nearly unnecessarily large fangs protrude from it which readily carry beads of its 'venom' when threatened or on the hunt. Spirit spiders live in 'families' of two to upwards of ten, and they are remarkably coordinated when it comes to herding large prey into compromising locations - usually their webs.

There are two features of Spirit spiders which set them apart. First are their webs, and second is their venom.

Webs
Spirit spiders lay out incredibly thick yet surprisingly brittle and hollow threads of webbing. Working together in their families they create chaotic, winding webs which cover many square metres. The threads are not sticky and indeed are too frail to even support the spider's weight once laid. However, they are coated with a liquid which quickly freezes in the sub-zero temperatures into nasty, icy shards.
Prey is herded into their webs which promptly shatter into a spray of sharp ice, causing lacerations and disorienting their victim. It is at this point that the spiders pounce, sinking their glistening fangs into the doomed individual.

Venom
One might assume the Spirit Spider is so named for the eerie way it glides across the snow covered ground, or its camouflage creating ghostly flickers through the trees. However, this is not so. The Spirit spider is named so because the 'venom' it contains in ample amounts within its glands is in fact nearly pure Ethanol.

With a melting point of -114 Celsius, Ethanol maintains its liquid form even in the sub-zero climate of these spiders which makes it an ideal tool for incapacitation. The alcohol, usually at temperatures below -30 C causes instant frostbite and incredible pain to the victim. In addition, if the victim manages to get away the alcohol administered directly to their bloodstream will make a coherent escape nearly impossible, as they drunkenly attempt to stumble to safety. If enough venom is administered, the Ethanol content will cause alcohol poisoning.

This venom is highly prized on the markets and many exotic beverages are made out of it. This means that hunting these spiders can be a lucrative - if deadly - business.
Some more wealthy merchants and aristocrats will pay good money for youngling Spirit spiders too, if they can be caught. They keep them in glass walled tanks and allow the arachnids to bite them whenever they want that 'instant hit'. This thrilling yet ill advised method is called 'Frostbiting'.

One final thing to mention - The spiders have a weakness which can be exploited. Ethanol is extremely flammable, and it seems that Spirit spiders are somewhat... Explosive. A well-aimed burning arrow can easily end the spider's hunting with a resounding 'Boom!', and if other spiders are close enough a satisfying chain reaction can easily occur.
Just one word of advice. For the love of the gods, don't go running up to a spider and start beating it with a flaming torch!