So, I created MONSTERS, creatures that specialize in guerilla warfare, sabotage, and terror. I immediately knew which one to make first:

Vashta Nerada - The Ravenous Shadows

Terror level: 10/10 (doubled sanity damage against British schoolchildren)
Toughness: 6/10
Stealth: 10/10 (they can be in ANY shadow)
DPS: extremely-high against organic creatures, negates unsealed armor

Weakness: Despite being impervious to gunfire, strong acidic/basic substances sprayed over an infested area, open flame, and/or extreme heat can decimate swarms if they can't get out of the area fast.

Vashta Nerada are swarms of dust-speckle-sized creatures that live together in clusters. These clusters make home in and disguise themselves as shadows. When you make contact with a Vashta Nerada cluster, it doesn't react violently (if at all) at first. However, if you let it envelop you or try to go too deep, it will kill you in an instant, leaving only a spooky scary skeleton behind.

Overall, high-octane nightmare fuel

Sounds like a neat terror unit, one that can simultaneously ruin morale, up casualties, and destroy supplies without even knowing how to use a gun. Too bad I don't know what its internal workings should be.

There are three pillars that make the flesh-melting shadow the flesh-melting shadow:

  1. Speed: It has to keep up with other people's shadows.
  2. Stealth: These swarms also have to be able to blend into shadows.
  3. Nom-Nom: It has to be able to consume flesh at a rapid pace.

Obviously, we can't reach the OG Vashta Nerada (you simply can't eat a whole human in less than a second), but we can try to create something similarly terrifying and powerful.

So, how could a scientifically plausible swarm of artificial beings fulfill those three criteria?

EDIT: This is NOT a duplicate of the question Can a 2D object living in a shadow be examined in a 3D world? as it is asking how something similar can be functional as a weapon in the real world, not how such a thing can be studied, or how a true 2D being can exist.

  • 2
    $\begingroup$ Consider balancing this by having the DPS be proportional to the size of the swarm. A solitary creature will take longer than your lifetime to devour you, while the OG Vashta Nerada is a super swarm which can devour you in seconds. $\endgroup$
    – Mathaddict
    Oct 20, 2020 at 20:56
  • 1
    $\begingroup$ @Mathaddict Well, I assumed clusters that do attempt to devour you are already grown-up. $\endgroup$ Oct 20, 2020 at 20:57
  • $\begingroup$ Is "gorilla warfare" the kind of warfare practiced by gorillas, or is it a misspelling of guerilla warfare? $\endgroup$
    – AlexP
    Oct 20, 2020 at 22:06
  • 1
    $\begingroup$ Yikes! I forgot that gold science-based badge lets me wield a hammer! Meph, take a look at that old question of mine. I think they're fundamentally the same despite some of the details in your question - but I would have preferred the concurrence of the community. Do you agree or disagree that there's a difference? If you believe the two questions are different enough, I'll retract my VTC. $\endgroup$
    – JBH
    Oct 21, 2020 at 1:40
  • 1
    $\begingroup$ @JBH I thought his was more about if the things could be made functionally as weapons, rather than if they could be true 2D beings or how they could be studied. That's how I answered the question (okay, I might be partial) but I think they're different. $\endgroup$
    – DWKraus
    Oct 21, 2020 at 3:02

4 Answers 4


Mosquito Territory:

I would make your Vashta Nerada to look almost identical to mosquitos. The speed is a little low, but mostly mosquitos can keep up with people (at least Minnesota ones). Functionally, they are delivery systems for nanites. Each mosquito is a tiny signal receiver for a computer signal that actually operates the swarm remotely. They would be stealthy because they look like a natural part of the environment, even mimicking their sounds and behaviors. Only these are not merely vile, blood-sucking horrors.

They sneak up on you, flying overhead and dropping from the sky to make a stealth approach. Or, they can simply act like a swarm of mosquitos. Chromophores on the wings and body allow them to adapt to a victims clothing, so they can plaster themselves to a person and cling invisibly. Then, like a tick, they crawl under the clothes and apply an anesthetic to you so you don't feel them killing you. If quick death is preferred, they inject neurotoxin, paralyzing you, and your heart stops. If they want to go the gruesome route, they inject nanites that work like enzymes and respond to a wireless or hormonal signal (or an EMP, so trying to "kill" them merely triggers them to kill), rapidly metabolizing you from the inside out at a predetermined signal.

This is not "flash consumption" on first attack, but instead a stealth approach. The actual death and even the consumption can happen very quickly, once they've gotten their hooks into you (literally and figuratively).

The horror of these things is magnified by the fact they look like mosquitos. Everywhere people find mosquitos, they will never know if they are bugs or tiny killers come to murder them. The same enzyme-like attack used to dissolve people can be applied to mosquito nets, so they can cut their way in. They aren't really mosquitos, but people would likely use massive quantities of pesticides to counteract the attacks. This only means that when they directly attack you (instead of stealthing up to you), you know it's them and not just bugs. Only there may be nothing you can do to stop them. Like an infection, you know they've already gotten you.

To add insult to injury, once they've injected you, they could fly or crawl to your ear and use their wings to communicate. The victim can now be captured easily, as the alternative is to dissolve where they stand. They could even fly to someone's ear who HADN'T been injected and lie. Are you willing to take the risk?


Take a look at this:



Flesh-eating bacteria exist, and they act pretty fast. Perhaps your organism could be a variant of this, albeit a bit larger and able to cast a shadow?

As a commenter pointed out, this does not solve your mobility problem. It's not clear how buruli move or spread. Perhaps wings could be considered, but what if they were jumpers like fleas or grasshoppers? Fleas are known for jumping from victim to victim, they can go on average 20 cm (8 inches) away.

  • 1
    $\begingroup$ Welcome to worldbuilding. You might be able to elaborate this into an answer, but it is pretty thin, and doesn't match all the criteria. Take a bit to consider how to add motility to a swarm. Also, look up Dr. Who "Quiet in the Library," which is the source inspiration for the question. $\endgroup$
    – DWKraus
    Oct 20, 2020 at 21:58
  • $\begingroup$ OK Cool, apologies it's not there yet. Give me a few minutes to flesh it out (sorry) and hopefully I'll be much better poster (please don't hurt me) $\endgroup$ Oct 20, 2020 at 22:34
  • 1
    $\begingroup$ I actually considered necrotizing fasciitis for this question but couldn't figure out how to make bacteria fly. :) $\endgroup$
    – DWKraus
    Oct 20, 2020 at 22:52
  • $\begingroup$ Might not have to be bacteria, could be a very big virus, which can be airborne... And if it's represented as a shadow, then flying might not matter, it might be able to climb up... Shadows are cast on surfaces, so therefore no technical thing requiring them to fly...? Oh and SNAP on necrotizing fasciitis, but I've leant towars Buruli because it's what's got our local townships and suburbs scared witless $\endgroup$ Oct 21, 2020 at 0:09

I don't know of any one creature or any one reasoning that would explain everything in a scientifically logical way. A combination of scientific logical reasons can be combined into your creature.

  • Speed: It has to keep up with other people's shadows.

The speed a microscopic creature can travel is largely dependant on the limb design and the medium it is travelling in. Working out the body-size vs speed ratios is actually not really necessary as your swarm isn't keeping up with other people's shadows so much as tagging along.

Rather than being super-fast for their size, they have a super-strong clasping/grip-locking ability (more dung beetle strength than tick speed). Their movements aren't directed at keeping up with fast moving prey (they are latched on) but rather with just staying in that victim's shadow.

Once your victim enters some infected shadow region and given the swarm enough time to realise there is prey the vashta nerada closest to the victim actually latches onto the skin/clothes/outer covering of the prey and the rest of the swarm latches onto each other like a series of long chains/netting. All the swarm has to do is keep a strong grib and direct their lateral movements so that they are always following in the shadow of the victims. The vashta nerada at the back rows then start climbing over their comrades towards the victims juicy ankles, until all of the swarm is in direct contact with "food". Dinner is served.

  • Stealth: These swarms also have to be able to blend into shadows.

These swarms have chromotophores on their skin/shell/scale surface which helps them blend into the background.

These are specialised chromotophore cells and may be; extremely sensitive to light/heat, which is why they hide in the shadows; and easily damaged by sudden changes in temperatures, which is why they are prone to damage from open flames/strong acids and bases/ extreme temperatures.

This sensitivity to heat could also explain how the swarm is attracted to those victims who enter the shadows, as well as why it may take a little time for an attack to commence.

  • Nom-Nom: It has to be able to consume flesh at a rapid pace.

The piranha-like swarm doesn't consume the flesh entirely on the spot, from one end to the other. It rather chooses to devour the flesh in a haphazard way that results in the flesh breaking down into into smaller and smaller chunks. So your flesh and limbs literally start falling off in chunks to the floor in front of you...and is then fully consumed at a more leisurely rate (or whenever the swarm can get to it).

As the swarm prefers a constant environmental temperature, they are naturally inclined to first finishing off the living victim with warmish blood temperature (which may still rise and fall as the attack commences), before returning to the rapidly cooling remains on the floor.


You could borrow from the Southern Californian Mite, if you want an explanation of how something small can be wicked fast.

"When drawing comparisons between different classes of animals, an alternative unit is used for organisms: body length per second. The fastest organism on earth, relative to its body length, is the Southern Californian mite, Paratarsotomus macropalpis, which has a speed of 322 body lengths per second.[3] The equivalent speed for a human, running as fast as this mite, would be 1,300 mph (2,092 km/h)"



You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .