The Death Worm

A tubular column on using folklore in tabletop RPGs

Heatstroke. Sandstorms. Dehydration. All of these are very real threats to one’s survival in the desert. But before any of these natural causes can claim you, there’s something even more dangerous lurking beneath the sands.

It’s not just any worm.

It’s a death worm.

I. The Worm, The Myth, The Legend

Known in the West as the “Mongolian death worm”, this creature is referred to in Mongolia as the olgoi-khorkhoi (“large intestine worm”).

The olgoi-khorkhoi is several feet long, shaped like a sausage, and lacking a head or neck. A dark red colour, it appears almost like a living intestine, hence its name. Some accounts give the creature spine-like projections at both ends of its body too¹. The olgoi-khorkhoi spends most of its time hidden beneath the surface of the most desolate parts of the Gobi desert, burrowing through the sands.

So, why is it called a death worm? Well, for more than one reason. First, its allegedly so poisonous that merely touching it can be fatal. And if that wasn’t concerning enough, some stories furnish it with a ranged attack, letting it kill at a distance. This is accomplished by either spraying a corrosive venom or by discharging a lethal dose of electricity².

So, if you ever take a trek across the Gobi desert and stumble across a death worm, here’s some local advice on the subject: just steer clear of it!

II. The Reality

The olgoi-khorkhoi first came to Western attention as a result of American paleontologist Roy Chapman Andrews’ 1926 book On the Trail of Ancient Man. In it, he describes hearing about the creature second-hand at a gathering of Mongolian officials:

"None of those present ever had seen the creature, but they all firmly believed in its existence and described it minutely."³

Stories of a 'death worm' fascinated people back in America, and numerous expeditions have been launched over the years to look for it. Alas, no one has ever been successful in finding any evidence of its existence. Nowadays, the consensus seems to be that the olgoi-khorkhoi's powers are apocryphal, and that the death worm itself is likely to be a misidentified sand boa⁴.

Photo of a Sand Boa by Benny Trapp

Using the Olgoi-Khorkhoi in Your Game

Now you know the story, how can you use it in your game?

A Guard Worm

Why settle for having a yappy dog or poisonous snake guard your belongings when you could entrust them to a death worm? Just deposit one or more into a sandy pit alongside your most valuable treasures and you can be sure no one will want to touch it. Just make sure when you throw food down there to feed them that you say safely out of poison/electricity range.

An Exotic Pet

Everyone likes having a pet that gets people talking, and what’s more eye-catching than owning something called a Mongolian death worm? If you ever need to establish exactly what sort of person an NPC is quickly, just have them proudly show off their (allegedly) domesticated olgoi-khorkhoi. And if your PCs are investigators or trouble-shooters, they can easily become involved when it turns out owning a death worm as a pet is likely to cause problems—especially if (when) it escapes!

A Prelude to (More) Worms

As with similar creatures in pop culture, you can also always go with the idea that the olgoi-khorkhoi is actually the baby or larval form of some much larger monster. If the baby is this dangerous, what could it possibly be like when it’s fully grown?

Perhaps the olgoi-khorkhoi are aliens, ones who entered our world through an ancient portal and could never fully grow outside their home. This portal, now deactivated, was hidden long ago when the desert sands covered up the structure (or city) it resided in. Unluckily for your PCs, whether they be D&D adventurers or Call of Cthulhu investigators, the true location of this structure has recently been relearned. Now, the party needs to reach it before the bad guys do, lest they widen the gateway and let something titanic and far more horrifying through!

Lumbricus terrestris (2010) by Vega Asensio

Olgoi-Khorkhoi Statistics (Old-School)

Armor Class: 7 [12]
Hit Dice: 3* (13 hp)
Attacks: 1 x bite (1d4 + poison) or 1 x electric discharge (1d10 + paralysis)
THAC0: 17 [+2]
Move: 90’ (30’)
Save As: Fighter 3
Morale: 8

▶ Ambush: Hides beneath the surface of the sands, bursting out when something walks within 20’.
▶ Poison: A character who is bitten by the olgoi-khorkhoi, or who touches it with their bare skin, must save versus poison (with a +4 bonus) or die.
▶ Electric Discharge: Up to 50’. A hit leaves the target stunned for 1d6 rounds (save versus paralysis). Can be used up to three times per day.

Although usually only a few feet in length, rumours persist of much larger olgoi-khorkhoi that can rival even purple worms in size. Such creatures are said to produce lightning that vaporises any target it hits.

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And that’s it for death worms!

Thanks for reading; Mythoi will be back again in a fortnight for another fantastical piece of folklore to use in your role-playing games!

Penny for your thoughts: What’s your favourite memory of fighting a giant worm?

~ A.C. Luke

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Banner Image by Pieter Dirk, used under CC BY-SA 1.0

1. Shuker, Karl. 2002. The Unexplained: An Illustrated Guide to the World's Paranormal Mysteries. Metro Books.

2. Radford, Benjamin. "Mongolian Death Worm: Elusive Legend of the Gobi Desert". Live Science. Retrieved 20 November 2022.

3. Andrews, Roy Chapman. 1926. On The Trail Of Ancient Man. G. P. Putnam’s Sons: New York and London.

4. Ах, Гоби! Путешествие по Монголии в поисках легенды" [Ah, Gobi! Journey through Mongolia in search of a legend]. Novaya Gazeta. Retrieved 20 November 2022.