In my story with magic based around the manipulation of electromagnetism, I need the characters to have a hand-wave electric organ. This electric organ is about 10 cm per organ with the capacity to generate magnetism. The problem is that the organs are large and I can’t think of any spaces that would fit the electric organs.

So my question is if any areas in the human body can fit three 10-15 cm electric organs.

Edit: There are three organs one for creating extremely high Tesla magnetic fields and the other is for creating immense electric currents. One organ is essentially a homopolar generator to generate currents and the other organ is a superconducting electromagnet powered by another homopolar generator. The last organ is essentially a laser powered by electricity created by the homopolar generator to allow for lightning blasts. Also, the skin of these characters is essentially superconductive so they can be immune to electricity.

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    $\begingroup$ Note that if the electricity produced by the character's organ exceeds even a small amount, it can cause pain, uncontrollable movements in the circuit that is formed, or plain death. That's one of the many things you'll need to handwave :). $\endgroup$ Nov 9, 2023 at 21:33
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    $\begingroup$ You need to be a bit more specific about size - 10cm by what? A 10cm hairlike thread can go anywhere, a 10cm cube won't go at all, a 10cm long "sausage" could probably tuck in among the intestines... $\endgroup$ Nov 10, 2023 at 13:38
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    $\begingroup$ Multi-tesla magnetic fields are hard to generate even with large, dangerous, power-hungry, heavy mechanism, even when you're using superconductors. What will probably happen is that you'll power up your supermagnet, and promptly receive multiple fatal wounds from nearby ferrous objects accelerated to bullet-like speeds towards you. Given that you're basically handwaving in magic, I wouldn't sweat over the details too much. No answer is going to withstand much scientific scrutiny, if you get the power levels you're asking for. $\endgroup$ Nov 10, 2023 at 14:02
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    $\begingroup$ This is a totally flippant and useless comment, but: The title made me wonder why anyone would want to implant a large keyboard instrument in a human. $\endgroup$ Nov 10, 2023 at 20:56
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    $\begingroup$ @WayneConrad I was thinking the same: one of these perhaps? $\endgroup$ Nov 11, 2023 at 3:53

6 Answers 6


This is a Frame Challenge

  • You appear to be setting the size of the organ without first deciding how the organ operates. Unless you have a reason for such a large organ that you've not explained, deciding its size before deciding its operation is putting the cart before the horse.

  • Similarly, you're thinking in terms of one organ. However, given the brief description of what you want that organ to achieve, it makes more sense to have multiple organs.

  • You mention that it's an "electric organ" and that's likely leading people to make some assumptions. However, I'd like to point out that while electricity (in the form of the human nervous system) might be involved, the organ itself is not electric. It's magnetic. In fact, I think in your case it would help that you avoid the idea of an electromagnet and even avoid the idea of an electrically conductive ferro magnet and stick with the idea of an electrically non-conductive ferrite magnet, which is more along the lines of what a biological solution would be anyway.

What I think you might consider

It's important to work though what you expect your characters to do with this ability before you design the rationalization for its existence (create the organ).

Let's say there is only one organ, that the organ generates magnetism, and that it's located within the sacrum, the bone at the bottom of the spine. What could you do with it? You could be the all-time world-champion of musical chairs, at least as long as the chairs are made of a ferrous metal. And you could, um... redirect explosive objects by running away from them. I just don't see a lot of practical here. If it's strong enough it could disrupt communications... something like an EM fart EMP, dontchaknow.

But... let's put something in the palm of each hand. Now we have something we can work with. That helps the person climb and hang onto things. It simulates telekinesis. And it can do everything I just mentioned if it were located in the sacrum.

But you have two hands... makes sense you have two organs. In fact, it makes sense that you have three. The two emitters in the hands, and the "control organ" that creates the enzymes/proteins/juju necessary for the two emitters to work.

OK, so where and what size?

Now that we know a bit more about the whats and why, we can address the where. The organs in the hands shouldn't affect how hands are used already — at least not to a great degree. I'm voting for a spot between the second and third metacarpus bones This organ wants to be small, the size of a cashew at most, but it will need to be hard (from a fleshy perspective) to rationalize what it's doing.

Does that matter? Of course not. People born with this organ wouldn't even know it's there. They would have been training from birth to simply deal with it. They wouldn't notice it any more than they notice their kidneys... unless someone hits them in the kidneys. Interesting aspect for your story, no?

The "controlling organ" wants to be in the brain where it's close to the action. I don't think it needs to be too terribly large, either. Maybe the size of a small grape or an M&M. But I'm thinking to tuck it in with the Thalamus, which is the "body's information relay station."

Now, you might have had a reason for the large organ...

This is why my frame challenge exists. You might have a worldbuilding reason for the large organ that you haven't told us. If you do, that reason is important and we need to know it. If you don't, or if the reason is story-based rather than worldbuilding, then I invite you to reconsider the design of your organ(s).

But, let's assume that we absolutely must have a 15cm organ. Just for the record, an average finger length (index or middle finger) is about 11cm and the average human heart is 12cm tall - so you're talking about an organ that's longer than the average human heart or average index finger. That's huge and the only practical place it can go is to replace the appendix or, perhaps, to slide it between the stomach and intestines. There isn't a lot of free space in the human body (as long as you ignore body fat) and that organ is absolutely enormous. Which is why I'm advocating redesigning it.


In the abdomen, easily

I disagree with the various posters that there isn't a lot of free space in the human body: the abdominal cavity is spectacularly flexible, and can comfortably accommodate your organ.

A fairly substantial fraction of humans will grow an entire whole new human inside their body cavity at some point in their life, and often will not show any sign of this process until the growing fetus is about the size that you suggest (and the fetus is surrounded by quite a lot of accessory tissue).

There are plenty of reports of tumours incidentally found when they are "the size of a grapefruit" or similar. As an example, a simple ovarian cyst (extremely common condition!) is not typically considered for surgical removal until it's 10cm in size.

On the topic of grapefruits, humans are capable of ingesting rather impressive amounts of food in strikingly short times - far too short for any plastic adaptation. Again, this is because the abdominal cavity is designed to be flexible. This food (or drink, or any other volume of ingested matter) does not replace air: it nudges the tissues around the stomach out of the way, gently rearranges the bowels, and generally finds space for what needs to be fit in.

In the opposite direction, corsets designed for waist training can comfortably reduce waist diameter by 5cm, upon first wear (before any training) - suggesting that there is, indeed, quite a lot of slack in a body cavity at rest.

  • $\begingroup$ Nice. You could also remove some non essential organs, at a cost. Reading your post I don't think its necessary. $\endgroup$
    – Dor1000
    Nov 11, 2023 at 12:47

Along the skin with fat

Though not quite in the description, I've looked at electric eels (a knifefish species) for inspiration. Their electric organs (main, Sach and hunters) consist of stacked nerve cells, which allow the eventual discharge right for the situation. Compared to eels, your organ seems small. The knifefish can become 2m long with a weight of 20kg. Even compared to the smallest electric organ of this fish, your proposed organ is still a huge reduction of the existing organ. And we do not even have any plausible width described!

As we're playing with the plausible anyway, I would attach it to the lowest epidermis of the skin. This way the size can be distributed all over the body. As the organ is stacked nerve cells, you can stack them under the skin from literal head to toe. This will offset the width, at least in an offhand plausible way.

Why the skin? Because the human body plan doesn't have much room for a new organ. There's only a few places I can imagine there's space, and fat cells around organs and under the skin stand out. Both can visibly take more space¹. If fat can do so, another organ can do the same. Fat cells under the skin can be arranged in many ways as well. From the difference in shape between men and women, to athletic people with fat or people where the fat extends most features. This offers a great selection of different ways to build and stack the nerve cells in many different widths, lengths and depths, giving you control over a 10cm or 100cm organ if you desire. All while masquerading as fat cells.

It is a relatively simple solution, with a flexible implementation and easily hidden in normal daily life.

¹See the obesity epidemic


Make the humans a bit bigger or fatter.

In a big belly there would be enough place for these organs and humans have proven to be able to live with that. Alternatively the humans could also be taller and have a longer waist area to make place for the organs. This might be more astetically pleasing than everybody being "fat", but would also have more implication on general dexterity of these alt-humans.


How about the forearms or calves?

For the magnetic organs, placing the organs in the forearms or calves might be promising. There is enough room to place the organs without major body changes.

The forearms are ideal for tasks that need precision, like manipulating metal objects with a magnetic field for example. If the organs are in the calves, then you might be able to use the organ to climb metal surfaces, which is my other idea. I would also put a pair of the same organ in the two limbs, I guess!


Preamble: If we look at the physiology of electric eels, electric field generation requires a certain arrangement (series or parallel) of electrocytes, but these can be flexible, rather like neurons. Hence, I don't see any obvious reason why for they need to be confined to a particular shape as opposed to say distributed (with appropriate neuron-like wiring) throughout the body.

  1. If you've decided that you need three 10-15 cm organs, what do you mean by this? A 10 cm long string? A 10x10 cm sheet? A 10x10x10 cm cube?

  2. What are your requirements when placing these organs? For example, you could just plop a 10 cm diameter ball on top of someone's head, but it seems like you want the organs placed such that the person looks reasonably "normal." So what's your definition of normal? For example, the average American is rather overweight, and with a bit of excess abdominal fat, it's not that hard to hide a 10 cm blob somewhere in that neighborhood without anyone noticing. On the other hand, if these characters have need to have a slim six-pack physique and the organs can be flat, you could place them like how some people in real life have implants to enhance the appearance of their pectorals, buttocks, biceps, etc.

  3. If the organs have to be bulky and the characters have to be slim, consider that otherwise healthy humans have spare capacity in their organs such that they can survive with one lung (do your characters need to be Olympic marathon runners?), one kidney, less than half of their liver, most of their bowels missing (how long do your characters need to go for without pooping?), et cetera.

  • $\begingroup$ Hi, welcome to Worldbuilding! As a heads-up: please refrain from asking the OP questions in your answer. Once you have earned a little bit of reputation you can ask for more information by commenting on the question. If you lack sufficient information to answer a question, please go through the comments first (also on existing answers). If it's still too vague, I would for now suggest finding a question that has all the info you require :) $\endgroup$
    – Joachim
    Nov 13, 2023 at 18:15

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