In my story there’s a character named Zane who finds out that he attracts “ghosts”. It’s only when he sees them that he realizes that they’re not supernatural beings, but floating octopuses that can be invisible. “Edit: they are see through and instead of chromatophores, they have organic lenticular lenses that they can consciously shift, just like normal octopuses with chromatophores, which makes them even more difficult to see”

Throughout the story Zane is trying to understand how they came to be and most of all, how he can train them. And while I was writing I asked myself, is this possible. Is it possible that ghosts are a species of airborne octopuses with a more advanced form of camouflage?

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    $\begingroup$ "Is it possible that ghosts are a species of airborne octopuses with a more advanced form of camouflage?" - just to be clear, you mean in your story, right? $\endgroup$ Commented May 20 at 1:45
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    $\begingroup$ In the Real World we cannot prove the existence of ghosts. Therefore, when you ask, "is this possible?" the answer is "no." But that's incredibly boring! You want ghosts? You got them! You want them to be octopi? You got them! You want help developing the rules governing your supernatural octopi so you can deal with them consistently in your story? That's what we're here for. The backstory that establishes the rules can be a great many things and per the help center, we don't help write stories (yet...). But being bit by a radioactive spider has been known to do cool things. $\endgroup$
    – JBH
    Commented May 20 at 3:02
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    $\begingroup$ Upvoted. This is the quality content that keeps me coming back to worldbuilding.stackexchange.com $\endgroup$ Commented May 20 at 4:36
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    $\begingroup$ Presumably relatives of the Pacific Northwest Tree Octopus. $\endgroup$ Commented May 20 at 10:56
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    $\begingroup$ What I want to know is, why do airborne, invisible octopi go around moaning all the time? Is it just that regular, aquatic octopi also go around moaning, only nobody's ever noticed it because they're so shy? $\endgroup$ Commented May 20 at 20:21

3 Answers 3


Sod it - Hell Yes!

Initially I was going to say that an Octopi's camouflage/colour changing ability would not be enough to render it 'invisible' to enough people to give the feeling of a Ghost...

But after I read the comments - I decided that answer was boring. And this is a Fun question.

So let's go on a trail of how believable we can make this:

Let's start with the Glass Octopus - Mostly see-through, but if we add in some pigmentation ability, I think we can get pretty close to being 'invisible' to most people...

In most Ghost lore - the people that tend to be most sensitive to Ghosts are... Children and Animals.

As we age, our eyesight gets worse - Children have the exceptionally keen vision needed to see these - and Cats/Dogs - well, they have other senses.

Next up we have stories of Ghosts passing through objects - well Octopi are well known for being able to traverse spaces that are seemingly 'impossible' to move through - owing to the only solid part of their anatomy being their beak.

How would they fly? their diet creates an excess build-up of Hydrogen gas, which makes them mostly neutrally bouyant - they move like squids, filling up an air-sack and blasting the cold air to move - that feeling of cold air people experience when they 'encounter' ghosts? That's just the out-jet of these Octopi moving away!

The feeling of being watched? Octopi have very big eyes and sometimes those eyes catch the light - and that subconsciously alerts us to being watched - but our adult eyes aren't sufficient to determine the cause.

Why do Ghosts seem to visit people who have recently lost a Loved one? or Instill a feeling of Dread? Well - they produce a mating Pheremone that is similar the pheremone that humans produce when they are scared (the smell of fear) this means that when they are in their mating period - this is released by them which humans pickup and makes people feel uneasy - and when people are grieving, they release a similar chemical and sometimes over-eager younger Octopi come around hoping to find a mating partner - only to find someone recently deceased.

I could go on - but hopefully you get the jist.


After reading the comments (again) - Moaning - the Ghostly moaning is also a side effect of the Octopi blowing air to move about - However, it is closely associated with grief because when it is Mating season (see the above about Pheremones) the Males engage in elaborate aerobatical displays to attract a Mate and this requires more air to be exepelled than normal - which creates the ghostly moaning.

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    $\begingroup$ Ectoplasm: a damaged limb that got separated from the main body and started to decay, causing it to become gooey. $\endgroup$ Commented May 22 at 7:44
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    $\begingroup$ +1 for 'Sod it' $\endgroup$
    – ThaRobster
    Commented May 22 at 9:53
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    $\begingroup$ They eat bugs, which is why they prefer spooky old houses and tangled old forests and sometimes exhibit a pale glow. :) $\endgroup$
    – g s
    Commented May 23 at 20:54

Yes and No

Metaphysically, "ghosts" as we typically understand the phenomenon are simply the unembodied spirit of a person casting a shadow into our world. They are basically part of us in a sense. If this is the kind of "ghost" you mean, the spirit or soul of a person who has passed on, then the answer is no.

On the other hand, if what Zane is seeing is a kind of creature he does not comprehend, I can easily understand that he might interpret a mostly invisible octopoid creature or person as a normal ghost. The question here is really one of your character's interpretation of his own reality. If his reality comports with ours, then his interpretation will be wrong. If his reality is different --- if in your world "ghosts" are actually invisible octopoids, then his interpretation would be correct!


The Festo Air Jelly is a drone with a jellyfish-like action. Many parts such as the paddles could be transparent. Other parts could be made thinner, or painted black. This would still be visible in good light, but if it only appeared at night then it would be hard to spot. Add some luminescent display on the surface, and you could get something very ghostlike.

So, we could make something that works as described. But could it happen naturally? It is hard to see how something natural could capture helium. It might be able to generate hydrogen, but could it keep it? It would be very fragile, and easily damaged by wind.

Let us get seriously weird, and let this exist in vacuum. It does not have to survive wind because there isn't any. The creature could use a very open aerogel-like structure, and so be almost transparent. It could have a limited muscle-like action like an electrostrictive gel, except it would be going from an extended form to a compact form without expelling anything. If it is only seen against the dark background of space, it would be hard to spot, unless it made itself visible by contracting to increase its density, or giving out light.

It would be delicate. You could probably put your hand through it without feeling it. Suppose it had some ability to repair itself. Suppose it tore along planes, leaving positive charges on one side, and negative charges on the other. If it did not tear all the way through, it could reform itself using electrostatic forces.

Frame challenge: maybe the creature is not one creature at all, but a swarm of bugs that glow and synchronise with their neighbours. They can appear in low light, glow in a see-through way, change shape, then vanish. They just look like a squid.

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    $\begingroup$ I dunno that using hydrogen instead of helium would make the creatures (more) subject to wind damage. But it would make them explosive, which could be pretty exciting. $\endgroup$ Commented May 20 at 18:32
  • $\begingroup$ I don't think Richard meant hydrogen would make it more subject to wind damage than helium; just that anything lighter-than-air would have to be thin and fragile. I think the point about hydrogen is just that it's easier for life on earth to produce, as helium is a rare element. It would still take a lot of energy to separate hydrogen from compounds, but at least the element is abundant. $\endgroup$
    – LarsH
    Commented May 22 at 10:35
  • $\begingroup$ I like how making them nocturnal helps explain how hard they are to see. Yes, these jellyfish/octopi would be sensitive to wind. I imagine the effects would be similar to what natural octopi experience under water during a storm? So perhaps they shelter in crevices when it's windy? Perhaps wind protection is the reason why ghost octopi are often seen around human houses? $\endgroup$
    – craq
    Commented May 23 at 4:44

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