Fungi that control ants and other other small animals, internal parasites with authority over their victims...... old story.

I'm looking for an external parasite with authority over their victims.

The authority can't happen through:


-Money/currency/assests: it must be parasitism not an exchange of services for goods


-Pheromones (yes pheromones would be the best choice since no living being on earth is immune, but mutations rule that some may respond differently to the same chemical and some may develop resistances)

I want the parasite to control its victims through a system that animals can't develop a resistance to over time. For example, this excludes chemicals, since we humans develop resistances to almost any chemical making them weaker over time, even cocaine or pheromones.

This should be impossible with the new authority system. What external forms of ''mind'' control are possible given modern science?

  • $\begingroup$ Recommend you clarify what you mean by external. Since this is a parasite, it's probably attached. Can it jack through the skin (like old SF trope of alien bug on back of neck)? $\endgroup$
    – legio1
    Commented Sep 24, 2021 at 17:54
  • $\begingroup$ Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking. $\endgroup$
    – Community Bot
    Commented Sep 24, 2021 at 17:54

4 Answers 4


Classic Conditioning

This parasite can 'train' it's subjects similarly to how humans train pets: classic conditioning. Just give it a way to inflict a punishment, like pain, in a quick timespan. Then it simply punishes whenever the subject does something it doesn't want, and the subject will eventually modify behavior to avoid the punishments.

There is not typically resistance to this, in fact the opposite - conditioning tends to become more effective over time.

To allow for quicker and more detailed training, you could also give the parasite some form of reward. This may fall into what you consider "exchange of services" or "mutualism", but if it's a non-beneficial reward, like a dopamine injection, really good smell or sensation, etc. then I would think it should still work.


Neural implants

Hijack the victim's neural pathways and stimulate their muscles in any way you want. We are close to achieving that with roaches. They become resistant to neural manipulation within a few minutes of electrode attachment, and become completely immune over time. But with every generation of neural implants for them, the time they are under control of a smartphone increases:

Following a brief surgery you perform on the cockroach to attach the silver electrodes to the antenna, you can attach the backpack to the roach and control its movement for a few minutes before the cockroach adapts. When you return the cockroach to its cage for ~20 minutes, they "forget" and the stimulation works again. Once you receive your RoboRoach in the mail, follow our online surgery instructions and videos and you will soon be on your way to becoming an expert in neural interfaces. After about 2-7 days, the stimulation stops working altogether, so you can clip the wires and retire the cockroach to your breeder colony to spend the rest of its days eating your lettuce and making more cockroaches for you.


Without magic or Psionics (aka mind magic)? You can't, not unless you don't mind them simply not being completely inside.

I'm assuming by the examples you gave that by "authority" you mean the parasite can control what the victim does either fully or up to an extent. Problem is that, by default considering earth's biology, a parasite needs access to what the victim has inside of it, and that is true for every single parasite species on earth. You want to control that ant's brain and have it climb to the prefect place to release your spores? Find your way inside it. You want access to that animal's sweet post-digested nutrient goodness inside its intestines? Find your way inside it. You want blood inside their veins? Find a way inside them (because technically making a cut through the veins to get the blood is still a way to get access to their internal portion, even if that includes breaching them). You want to becomes that fish's tongue and live inside its mouth feeding on nutrients provided by its bloodstream? You guessed it. Find your way in and get that tongue out.

And that is the problem about your context: the closest potential thing you could use within the bounds of earth biology are, well, pheromones, but that would rely on the creature understanding said pheromones to begin with (also, yes, ants communicate through pheromones, but pheromones don't really work as some kind of chemical control panel where each pheromone dictates and action. Creatures like ants use them to share information, but instinct plays an important role into determining who does what and when depending on the information relayed by the pheromones).

Your best bet for some kind of control over a victim with zero physical interaction would be magic or some kind of powerful Telepathy, both of which aren't exactly based on reality.

So essentially, that leaves us with the last best option: if you can't reach their brains and nervous system through mind powers or magic, reach it through a needle.

Essentially, the creature latches onto the back of your neck, sticks a needle into your brain through the critical opening in your skull meant for the spinal cord to have somewhere to access it, take control over both hypophysis and other parts of the brain and its set. You don't even need to take control over the full brain, all you need is for it to twist it just enough to make you no longer see the thing attached to you as something harmful or which shouldn't be there. After that, linking itself to the nervous system, it will interpret what the body needs and take over what both hyphophysis, the hippocampus and other portions of the brain do, particularly regarding hormone production.

Why hormones? Because they're already produced by you by your own body, dictate a good portion of how you function and how you feel, and if you ever gain immunity to them, there's a chance that you'll die without some sort of medical assistance (diabetes type 2 for example is what happens when your body becomes resistant to insulin). You want the thing to do something? Teach it. Release reward hormones that make it feel good when it obeys the voice in its head and make it feel like garbage when it doesn't. With enough training, you hopefully get something that does as the voice says unconditionally.

In such a relationship, the thing cannot be considered as a mutualistic organism, the thing it's attached to could live just fine, if not better off, without it. Yes, it's not completely outside of the victim and it technically is relying on chemicals, but at the same time, no creature can develop a resistance to it, because it's parasitism relies on it having a brain with openings through which it can link to the spinal cord and using hormones, both things it cannot avoid and will likely die in case it does.


In the end, this answer is related to Cain's answer, which I upvoted. I agree with Cain, it requires intelligence in the parasite to actually control the host using (classic) conditioning.

RW examples of external parasites

Some predators keep prey alive, for keeping the meat fresh, for later consumption, like some large spiders do. But that behaviour may also be regarded as "predator" rather than "external parasitic". Anchor worms may be a better example, they attach to fish, they don't penetrate the body. They also don't need to control the host, the fish won't notice its presence. Other examples of external parasites are flees, mosquito's, ticks, lice..

An external parasite controlling the host

My above examples don't include parasites that actually control the host. The host would tolerate them, rather than being subjugated by the parasite. One example of animals controlling other animals is aphids which serve as cattle for ants. You could label the ant as the parasite.

Humans could be regarded as external parasites controlling animals

It is all a matter of perspective.

Suppose, some other intelligent species will take over the Earth, in a far future, and they attempt to write the history of nature on Earth, including humans. Humans could get classified as extinct, furless external parasites, affecting a lot of species. Controlling them.. whether it is cattle, breeding fish, or breeding mink to produce fur coats from them, in fact humans are dangerous external parasites, that are able to actually control animals they prefer to eat, or use to harvest their fur. They may even control other animals (like dogs) to help controlling their "hosts".

  • $\begingroup$ If my memory isn't failing me, the relationship between ants and aphids is called muttualism, not parasitism. Not only are the ants not harming the aphids or forcing them to produce honeydew (they already produce honeydew as a byproduct of their diet, the ants just make use of it) they also transport the aphids to better feeding grounds and protect them from predators, because having the aphids die is bad for the ants since they can no longer get their sugary mix. $\endgroup$ Commented Sep 24, 2021 at 21:29
  • $\begingroup$ @ProjectApex when the host survives AND is protected, the behaviour could even be regarded as symbiotic.. Same counts for humans in relation to cattle, to yield milk, or wool. Humans will never ascribe the label "parasite" to themselves, it requires another perspective to label that behaviour as "parasitic". That's why i put the future intelligent species writing Earth nature history. From a non-human perspective, it is easier to regard breeding cattle (like humans and ants do) as parasitic. $\endgroup$
    – Goodies
    Commented Sep 24, 2021 at 21:51
  • $\begingroup$ I have to say I disagree. If we forcefully breed them for the purpose of serving as food and providing milk, that's predatism and slavagism (the first because we eat them, the second because we make use of what they produce, although that'd have to assume we give them absolutely no benefit in return). From a strictly definition view, symbiosis means both get benefitted, while parasitism is by definition detrimental to one side and beneficial to the other. If you drink the cow's milk and give nothing back however, you're not a parasite, you're a slaver organism to it by definition. $\endgroup$ Commented Sep 24, 2021 at 22:58

You must log in to answer this question.