The skurj are the Land's answer to the good ol' fire-spitting dragon trope. Given the sheer horror and destructiveness of these creatures, it is altogether unsurprising that SRD decided to name them as he did, because they really are a scourge of the Land and indeed the world as a whole..
These massive flightless, sightless worms are clad hides of living stone (hence the Giantish expression 'were-menhir'), have hot magma for blood, and something depicted as 'a pulsing, rancid mass' for internal organs. They devour everything that exists, including their own dead, by which means they also multiply, rendering the obligation to slither behind the nearest bush to grunt and pant void.
Skurj emit a vile, putrid stench and radiate heat violent enough to blister skin. They attack anything within the scope of Einstein's law of relativity with kraken jaws and sharp, curving fans dripping with venomous lava. What cute, cuddly creatures, indeed! Not recommended as household pets for the under fives.
The skurj move by tunneling at dramatic speed through the ground, entirely unhindered by any type of rock or soil, which to them provides about as much resistance as a semi-set blancmange. Skurj have a particularly annoying habit of burrowing directly beneath their prey to then hurtle upwards suddenly, engulfing the unfortunate victim within their fell jaws. In making such upward lunges, skurj have been known to hurl their entire vast, bloated, worm-like bodies briefly into the air. In The Third Chronicles of Thomas Covenant, the skurj have been so busily rampaging across the earth and burrowing everywhere that, if the Land's inhabitants ever wanted to build a Metro or other underground railway system to speed up transport, there's be precious little tunneling left for them to do.
Apart from a well-hefted slice from a Giantish blade, the skurj have one other primary weakness - water. This is not so surprising, since the serpentine abominations are clearly some sort of elemental creatures of fire. Although of the merest intelligence, the skurj have an instinctive abhorrence of the slightest touch of water, which does to them much what salt does to a slug - except of course not many slugs grow up to 100 metres long, are red-hot and have fangs like machetes. (If they did, gardening would be a far more interesting pastime). Having said that, if Covenant and Linden been equipped with a pair of Super-Soakers™, instead of a white gold ring and the Staff of Law, things might on occasion have gone a whole heap easier for the forces of good.
The Swordmainnir love nothing more than a leisurely hunting of these fell beasts: slicing them open, tearing out their hearts (a special favorite of Grueburn's) and bathing in the scorching worm-slime, which they may do with impunity since, as you may recall, Giants are not physically harmed by heat. If only this fine activity had not led to a couple of deaths and torn-off limbs...
The other fractionally less serious side effect of skurj-slicing revolves around their utterly rank-smelling internal juices. So unspeakably vile is the reek of these that it would make a ravenous hyena stop dead and keel over at a hundred paces. The fact that the Swordmainnir love to go hacking at skurj so much and consequently getting drenched in the vilest of ichor may well explain why they so frequently seem to bemoan the lack of male Giantish company. It's hardly surprising... skurj blood is hardly Chanel no. 5. Then again, is a serious warrior supposed to smell akin to a summer meadow in full bloom? Substracts something from the credibility, methinks...
The skurj are controlled, up to a certain point, by the insane (and quite possibly inane as well) Elohim Kastenessen, who has merged himself with one - kind of like Jeff Goldblum does by accident in the movie remake of "The Fly". Except that there's no weird scientific equipment involved. Oh and Kastenessen did it on purpose. Okay, so not really that much like the movie.
The skurj are said to be a great peril that originates "in the far north of the world". Very mysterious (not)... that'll be an active volcano then, that has given birth to the skurj from within its eternally roiling and angry magma heart. You hardly need to be Sherlock Holmes or Hercule Poirot to work that one out.
The Elohim indeed *did* work this one out and further decided that a host of skurj rampaging all over the earth would look neither particularly fashionable nor elegantly chic. In typical Elohim style, they came up with a solution that involved turning one of their number into a large adamantine gate to keep the skurj locked forever more within their fiery crater birthplace. Needless to say, there were no volunteers for this most mind-numbingly boring of eternal tasks, so Infelice, the Elohim queen declared that she would pick a name out of a hat to decide who would become the Appointed and serve this Durance. (Being the Elohim, you may be sure that the hat used would have been the last word in fashionability and elegance).
However, Infelice, being a tricksy sort of woman - but damn, is she a babe - rigged the draw to ensure that Kastenessen became the Appointed, since she was seriously miffed that he had ignored her subtle flirting, spurning her to go off and get frisky with a mere mortal woman, Emereau Vrai, instead. Thus Kastenessen, dragged in spitting and cursing, was sentenced to his everlasting Durance for the unthinkably heinous Elohim crime of "no longer being cool"- which is probably why he went batshit nuts and is so permanently pissed at everyone and everything.