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As mentioned in an earlier question of mine, my particular world has a class of humanoids which have the magical ability to change into a single animal form at will. As detailed in the linked question, only clothing disappears and reappears on transformation, other items tend to fall off the animal body.

Since my world takes place in a story, there is going to be a fair amount of strife. Part of that will include enemies capturing some of these shapeshifters. Now holding a shapeshifter with a large animal form (such as a lion or a wolf) is not too hard. However, smaller creatures, particularly those which fly, becomes much more difficult. Particularly in the throes of combat.

Take, for example, a shapeshifter bat. Ideally a human-sized cage with very small holes or other such item would be used for capturing such enemies. However, when participating in frequent/guerilla combat, carrying a large cage around is simply not practical.

What kind of method using more portable materials (ropes, nets, etc.) could be used to capture humans that had the ability to change into small creatures? Ideally this is not too specific to a particular kind of animal (a mouse-shaped trap would not be very helpful against sparrows).


  • The containing element (ropes, nets, etc.) would not transform with the shapeshifter. Shapeshifting is based on self-image. Ropes are not part of that.
  • Shapeshifting occurs quickly (within seconds) and does not change the size of materials near the changing.
  • Animal forms have human intelligence.
  • Each shapeshifter has only one animal form. That is, a person with a bat form will never have a lion form.
  • Shapeshifters only have reasonably large forms. No microscopic parasites or insects. Assume that all shapeshifters are at least the size of small mammals (mice, rats, etc).
  • Shapeshifters can transform at will, but cannot be forced by outside measures. (There's no "button" to press to make them transform.)
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Can the captors tell what shape the captive can take? – Tim B Jan 22 at 10:58
@XandarTheZenon Unless I missread I do not believe OP gave any indication of Good/Evil. Also unsure how this is relevant to the question, both good and evil shapeshifters will have enemies, and those enemies might want to extract information before killing. – Selenog Jan 22 at 15:02
How much force can the shapeshifting apply? If you are inside a rat-sized cage, and shift to an elephant, do you automatically demolish the cage unless it was also big enough for an elephant? – Cort Ammon Jan 22 at 15:38
A common theme in fantasy is a material that contains or weakens shapeshifters. For example a drug (wolfsbane) or material (silver) that prevents them from shifting. – Tim B Jan 22 at 16:41
I know you edited a clarification: "This is not about how to snare a shapeshifter, but how to contain them after they have been subdued," but perhaps what makes it confusing is you mention early on "particularly in the throes of combat" and have it tagged as combat, whereas it seems the restraint idea is post-combat. Perhaps prison and/or tatics would be more appropriate, or even warfare. – ScottS Jan 22 at 18:45

19 Answers 19

up vote 36 down vote accepted

drug bag drag

Drug them with something that stops them from forming the self image needed for the change. Opiates or hallucinogens would probably do the trick, but details would vary. Simple alcohol might work well enough.

Then close them into a bag that makes it impossible to quickly escape if they do manage to transform. Any reasonably tear proof fabric will do. It just needs to slow unfocussed and drugged person until guards can deal with him. It will also make the body easier to control and move and allow putting opiates or alcohol inside the bag to sustain the stupor without also drugging the guards.

Since they can't walk you will have to drag them along. You can stack the bags on a cart or a sledge or some such. Details are not that important. You just need some way to move the goods.

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So far I think this is the best answer. Good job! – DonyorM Jan 22 at 12:39
What happens if you accidentally capture someone in a bag who transforms into a bear? To be honest, I think that sounds like a good scene that should happen in the story more than a problem with your answer. – Mark Jan 22 at 16:12
@mark: bear in a bag sounds like a truly terrifying children's gift... – Joe Bloggs Jan 22 at 18:06
Almost perfect! The bag should then be placed in a cell, so if the prisoner's form is big enough to tear the bag apart, he's still contained by the bars. This doesn't fit well to small creatures chewing their way through the bag, though. – loa_in_ Jan 25 at 0:08
Once the human shape is in the bag, you can put some chains around it in case it turns into a bear. – Davidmh Jan 25 at 11:32

This is very easy in the case of creatures that shapeshift to larger creatures, and also works fairly well on ones that shift to smaller ones, but it's dependant upon how fast the creatures shapeshift and when the 'self image' concept kicks in.

Essentially the method of containment consists of a collar, designed to be easily snapped around the neck, with four spring loaded bars that push inwards against the shapeshifters neck once closed. If these bars move too far inwards or outwards, the collar does something nasty. I recommend having spring loaded spikes inside the collar so that any transformation leads to an immediate severing of lots of fairly important bits of anatomy. Or fixed spikes if you know they transform to a bigger animal. Or explosives if you have access to them.

Now you have your shapeshifter pinned in human form and you can contain them just like a human. You can also use the collars to dole out punitive justice/mark out the shifters/any number of other purposes.

Adding in wrist/waist/ankle bands would help to reinforce this, and make it harder for anyone to transform without dying an immediate and grisly (or possibly even grizzly) death.

This doesn't work if the shifter 'snaps' from one form to the other via magic. It only works if there is a 'transformation' phase where the shifter is moving from one shape to another. It also falls down if the shifter starts to accept the collar as part of their self-image, but hopefully by that point you can assume they're pretty broken to your will anyway.

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That's actually a pretty good one. – DonyorM Jan 22 at 12:03
Hm, pretty close to my idea. I wonder why I had missed it before when going through the answers. How would you contain smaller than human ones (assuming they transform too fast for spring-loaded spikes)? – J_F_B_M Jan 22 at 15:10
Won't work on shifters whose animal form has a neck that is of comparable size to their human neck. Or if their animal neck is considerably smaller, but they can get their hands/claws into the collar and hold it in place while they transform. – Darrel Hoffman Jan 22 at 15:38
@DarrelHoffman I would say that is what normal handcuffs are for. – J_F_B_M Jan 22 at 15:50
@DarrelHoffman: If they're transforming into something of similar dimensions to a human then your containment problem is already solved: Contain them as you would a human. – Joe Bloggs Jan 22 at 15:52

Assuming injuries are taken with you from one form to another then break their arms.

They can still walk in human form, but a bird form cannot fly and a quadruped cannot run or even really walk.

If they do change form and it's smaller than human put a spiked collar on them and keep them in that form. If it's larger then force them to transform back and put a spiked collar on the human form.

Brutal but effective.

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I'd use Tranqulizers, personally.

If you're close enough to throw a net over them before they scamper away into the undergrowth or fly away, you're more than close enough to shoot them with some form of tranquilizer gun. Shapeshifting takes a couple of seconds so a good, trained shot would have more than enough time to hit them while they were vulnerable.

There are a couple of variables to consider:

  • what happens to the tranquilizer in the bloodstream of the shapeshifter if they change? Does the ratio of blood:tranq remain constant, or does the quantity of sedative remain constant through the change? If the latter, then you would have to choose your sedative carefully in order to ensure that they don't suffer an overdose.
  • Is shapeshifting a survival mechanism? As in, if put in a position that would stimulate an adrenal response in humans (fight or flight), will shapeshifters instinctively shift? If so, if the former is the case in the previous question you could give a dose too low for a human but ample for a small animal.
  • What happens to an object stuck into the skin of a shapeshifter when they change? Do they "fall away" as well? What if I have shot the human form with a barbed arrow in the leg, say? Does it just "drop out" during the shifting process? Depending on the answer, your sedative needs to be fast acting and quickly absorbed in order to take effect even if the dart comes out during the shift.

  • Finally, it depends on how important non-fatality is. If you want to catch them but it's not a complete failure if some die, then sedative overdose isn't too much of an issue. If it is critically important that some don't die, then you'd have to do some research beforehand though into just what they might turn into. Only as much as you'd have to do for any other method, though - a net is of questionable use if your shifter turns into a small burrowing animal and disappears under the earth!

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This is good, similar to Ville Niemi's answer, but it does present the issue of what to do when they wake up. Ville's answer handles this a little better. But it's still a good idea. – DonyorM Jan 22 at 11:17
Yeah I didn't see his till after I'd finished! – I Stanley Jan 22 at 11:22
"Does the quantity of sedative remain constant?" - This actually provides a great opportunity. If the total amount of sedative is constant, rather than the concentration of sedative, then you could dose a human-form shapeshifter with a lower amount of sedative. With the right dose of the right compound, it could keep them able to move around on their own, but disable them as soon as they shifted into an animal that's, say, less than half their human body mass. – recognizer Jan 22 at 16:25
Sedatives get absorbed by the bloodstream over time. You'd have to get the timing exactly right AND know exactly the mass they would shift to in order for it to work. Tough to plan, and hardly the easiest way of doing it – I Stanley Jan 22 at 16:38

For the simple answer, a double net. One heavy weight rope, maybe as much as 1" with a loose 6-10" weave, one very fine butterfly net style. The big beasts will rip the fine net but not break the heavy net, the fine net will stop the smaller beasts from getting through the gaps in the heavy one. You might even go for three layers to have an extra check on the cat/dog sized ones.

If you're trying to catch rats or mice, you're on your own. You've got at most a minute before they chew their way out of anything non-metallic.

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he can shapeshift several times to escape each layer... 1 to a rhino through butterfly net, then mosquito through the large net.. and if you have extra layers... yadayada yadayada – Tomer W Jan 24 at 5:23
@TomerW, if you read the question it's only one form per person – Separatrix Jan 24 at 15:22


You mentioned your world has magic, since that is the basis for the shapeshifting. Is there a class of magic that can be utilized for either casting spells or creating magic items? Something that allows for one or more of the following sorts of things:

  • Immobilize (i.e. paralyze, freeze, sleep)
  • Restrain (i.e. magic collars/nets that expand/shrink as needed)
  • Contain (i.e. magic cages that are like force fields, or where crossing their boundary, no matter how big/small, causes damage/pain/shock that prevents one from crossing [throws them back to the center of the "cage"])
  • Control (i.e. hypnotize, enslave, make into a "zombie")
  • Deceive (i.e. illusion to make them think that no matter what shape they take, a cage/restraint has transformed to contain them; delusion to make them think they are not strong enough to escape or incapable of shape shifting)
  • Suppress the magic of the shape shifting (i.e. anti-magic, whether broadly speaking or specific to suppressing the shape shifting magic)

Special Technology

If the world also has high tech, then things like:

  • Stun guns (regularly applied in case of "restraining")
  • Force field cages/cells
  • Hibernation capsules

But even if it is a low tech world, could some form of specialized technology designed around "naturally occurring" phenomenon been built to handle these creatures? They cannot be forced to shapeshift (per your requirements), but perhaps they can be suppressed from being able to (even though they can "transform at will," there are things I can normally do "at will," yet in special circumstances cannot do). So things like:

  • A form of rock that emits magic itself that suppresses the shapeshifting (kind of like a shapeshifter's kryptonite), which non-shifters mine to use in collars/hand-cuffs, but the effect works in a small radius from the rock (since it is emitted).
  • A form of 'poison' brewed from various plants, etc., that suppresses the shapeshifting (similar to the "drugging" noted in other answers, but one that is specialized against this particular "at will" ability).
  • A type of metal in which contact with the skin creates a magical disruption of the ability to shift.
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This seems pretty good. There are more normal magic users (capable of performing spells), and adding such a magic material does not seem unreasonable. – DonyorM Jan 22 at 16:40

Put the shapeshifter on a landmine. If his form is smaller, as he changes the mine blows up. Tell the shapeshifter about it. Demonstrate it. Make him fear it.

By landmine I mean any trap that works on the basis of pressure-plate. Spear-walls, multiple crossbows with trigger-wires aimed in the general direction of the 'shifter, for example, or pots of boiling oil above the 'shifter are valid examples too. You don't have to physically tie someone to a place if you can make him want to stay there for a fear of death.

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Well, you need to have a lot of specialized traps, one for every shapeshifter, basically, since a trap that work for a lion, don't work very well for a bat. And you need to bring them around, not really convenient... – Gianluca Jan 22 at 10:51
@Gianluca Not really for each and every shapeshifter. Just for a few kinds, such as large-medium-small. Put the large ones on a wooden plank above a large hole with spikes on the bottom, mid ones can get the net, small ones can get the landmine. It all really depends on what technology is available to the people. – Nikita Akopjans Jan 22 at 10:54
This would be really hard to use for shapeshifters with flying abilities. – DonyorM Jan 22 at 11:11
@DonyorM In general, if the transformation takes seconds, it still takes too long to be safe and sound to not get hit by an explosion that takes mere fractions of a second since weight of a person gets decreased, thus activating the mine. Depending on the way the transformation works, even it in its own right might change the weight of the 'shifter and activate the mine. It does depend on the technology level of your world though – Nikita Akopjans Jan 22 at 11:17
@DonyorM Actually, it doesn't. If you put a man on a landmine and he walks off? Boom, lost a limb. You put a wolf on a landmine and he steps off? Boom, lost limbs. You put a man on a landmine and he turns into a wolf? Weightchange results in explosion and boom goes the wolve's limbs. The guy turns into a bat? Boom, lost life. Man turns into a gorilla? Boom, injured limb. And you can choose what kind of a weight arms the landmine, so you can capture them in any form you want and act accordingly. – Nikita Akopjans Jan 22 at 11:24

The answers I have read so far are all nice, but usually seem to either go the one-size-fits-all or are too spezialized for field-use.
What I like most is the solution with drugs, but I fear you might run out of drugs before you run out of shapeshifters, so some passive(-active-mixed) means are required.

How to catch them:

If the Shapeshifter is significantly smaller than a human:

There is no real way to catch them except cornering them. While a normal mice may walk into your set-up trap, an intelligent mice will notice that something fishy is going on with that cheese on the spring. Of course you can set up traps that activate by entering them, but they are usually highly situational (like needing an unsuspicious hole where the shapeshifter will enter by himself). A lot of planning is required by the hunting party.

If the Shapeshifter is bigger or equal to a human:

Use standard hidden hunting techniques. Covered pits, manually or automatically triggered rope-traps, nets. Basically any way animals are catched in our world, except that it may not be obvious for a human observer.
The alternative is to simply hunt them down with weapons, ropes and nets (and, yes, tranquilizers).

If the Shapeshifter is in human form:

Use standard human-restraints in addition to this. No point in placing a collar around their neck when they can just take it off with their uncuffed hands.

For anything larger than a human:

Put a collar around a body-part that enlarges. Be it the neck, hip, ankle or even feet. When the shapeshifter transforms from human to elephant they would strangle themselves, when the restraint is around the feet (steel-shoe comes to my mind) they would cripple themselves with it.
Depending on time and availablity add any additional gear like Spikes (inward for example), Explosives (activated by tearing the restraint) or something else from your imagination.

For anything smaller than a human

If there is a part that stays the same during transformation, restrain that one. For this to work however the shapeshifter should not be able to use any (now unrestrained) body-part to free itself in a matter of seconds. In this case probably use the next method.

Use a self-fastening restraint. Mabye some kind of spring, that excerts a constant pressure can work. When the body-parts shrink, the restraint will shrink as well.

If the shapeshifter shrinks entirely out of any restraint, a bag or net is probably your only option. Remember though you only need to carry human-size bags, not elephant-size bags. If the shapeshifting happens toward the body-center, smaller sacks with self-fastening holes might work as well. The head, arms and legs go through the holes, when the shapeshifter shrinks it wll end up inside the sack with all holes closed (long enough).

If the Shapeshifter is in animal form:

Now that is where it gets tricky. Because there isn't a single form for all shapeshifters, we have to come up with some generally available restraints.

For anything smaller than a human:

Collars work again wonders for only slightly smaller animals (dogs, maybe cats, even some larger birds). Use sacks and/or nets for even smaller animals. It can't be healthy to enlarge from mouse-size to human-size inside of a 5 liter leather-bag.

For anything larger than a human:

Don't. At least not if you can force them to change to human form. How to force them? Be creative. Poke them (or threat to poke them) with a stick (read: spear), a sword, a gun, something poisond... the list goes on. If a shapeshifter is not willing to change to human form, kill him (or, if the mission does not allow that, threat him you will).
Alternatively tranquilize him and use some methods from above to at least tie it up somehow. As mentioned in the question you can not carry an elephant-cage.

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A possible solution is a fishing net with very small mesh (less or around 1mm) made with some resistant yet flexible material

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That was my original idea (my first encounter in the story has the captors using a net). However, this would be difficult to make general enough net. (Too large a net might allow smaller animals to escape. Too small wouldn't work for even a little larger animals.) – DonyorM Jan 22 at 11:17
Out of curiosity, why a too small shouldn't work for even a little larger animals ? – Gianluca Jan 22 at 11:27
I would think a raccoon would be barely affected by a mouse-sized net. If I'm wrong feel free to add that to the answer, I think that would make it much more feasible. – DonyorM Jan 22 at 11:30
If you build a fishnet with the "holes" small enough to contain a mouse, a raccoon had not a chance to exit through them, it the material is resistant enough. – Gianluca Jan 22 at 11:35

There's the solution used in fairy tales. Talk to your shape shifter and say you don't believe he could get as small as a mouse. Then he does, just to show you, and you trap him in a stout bottle.

You could fool him into going small by setting a trap - like precious stones or special food - in a small place.

Basically trap the guy as you would a mouse, and have an unbreakable bottle handy.

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Each shifter can change into only one animal form as per the OP. So this would only work on shifters whose form is a mouse (or other small animal). It'd be useless on anything that transforms into something larger. – Darrel Hoffman Jan 22 at 15:42

An alternative to Ville Niemi's answer in case you're anti-drugging, is a solid container. You didn't specify what happens when they transform into a larger animal (ex. elephant), so I'm not sure if they'd burst, say, a box during a transformation. If so, the container would needed to be reasonably large and without holes— we don't want prisoners who can transform into smaller animals slipping out.

You'll have to deal with the prisoner slamming against the sides and moving around when transporting him, but that's a secondary concern to your containment question.

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What about a pill that is made from a treated unstable metal

Pill that is made from a treated unstable metal with some kind of natural radiation which makes it stable and workable like other metals the process was rediscovered from an ancient alchemy text from the times of the earliest cases of reported shape shifting. While the treated metal would also change from a solid to a liquid when and only when it was was in contact and infected by the radiation that is only produced with the energy that is emitted during the process of shape-shifting. The earliest and later alchemist have never found a way to utilize it, it was a bounty hunting rogue who fashioned the first pill from it with a poison that powerful that a drop would kill an adult orc [:)] while his pills where crude they were very effective [3 drops in each would kill instantly the largest shape-shifter before they could complete their transformation] he would sneak up and drop one in the mouth of a sleeping suspected shape-shifter. They would choke while swallowing the pill in their sleep then waking them up facing a gun [or some kind of weapon] aimed at their head, shape-shifters would change to escape causing the treated metal pill to liquefy releasing the poison killing the shape-shifter halfway through the transformation process. This would allow the rogue to prove it was a shape-shifter and collect the bounty the non shape-shifters would be threaten to stop doing something they were not doing as cover story the pill would pass harmlessly through them.

Guess he made a deal with you or what ever and you now replace the poison with what ever you want tranquilizer?? As they are very small you can carry a lot, being made of metal you can make them to be almost indestructible as well. Magical and non magical users can carry and use the pill. Sorry about the lameish story but it helps my ideas follow and needs to fit in your world.

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This would work well, but I don't want to kill the shape shifters only contain then. – DonyorM Jan 23 at 1:44
you could put anything in the pill from poisons to magic potions or a knockout drugs, it would only be released into the shape-shifter if they changed shape :) but it is your world – user17347 Jan 23 at 12:19

Most physical abilities have some physical limits. A determined cat can generally squeeze through any hole it can get its head through -- but the skull sets an absolute limit. Unless your shapeshifter is completely amoeboid or completely free of size limits, there is likely to be some organ which simply can not be distorted past a certain point without taking serious, perhaps fatal, damage. The fact that things tend to fall off is not a statement that nothing will resist that tendency; a fine enough net (of some material that will resist chewing through) might be all you need.

Limitations make better stories, in most cases.

Barring that, use a magical force barrier. Fight magic with magic.

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What happen to the thing that was swallowed? What if you made him swallow a rock with a steel string attached to it? If it just magically fell off, the best way would be dose him with some kind of poison. Or as @Gianlua said, use a net.

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It's an interesting idea, but I think it wouldn't work with the transformation mechanism. It would also be very easily fatal. – DonyorM Jan 22 at 11:15

Let's go fishing!

No, really, you just need a net and a hook.

You can hook your shapeshifter if it's large enough (terrier dog size and over, otherwise you'll crush him) and tie him. You can hook the 'shifter anyway you like: hand hook, throw him a spear, shoot him with an bow/crossbow with a tied arrow...

If you want a single size hook version, you should make the hook large enough to tie the smallest shape without killing the 'shifter. And remember, the bigger the shape is, more hooks you will need for a single 'shifter. Take also in mind that if you pierce a 'shifter while it's on his largest shape, his wounds will become more massive if he gets small, but I don't think it'll die.

If your shapeshifter is in a shape too small to hook him, catch him with your net/bag. You will notice when he gets bigger (it's not an instant process), then hook him and reuse the net/bag as you wish.

Your 'shifter will feel lots of pain, but won't die and will get weakened enough to fight. If his legs aren't hurt there is the advantage that the 'shifter can still walk by his own, so you just need to pull him and not carry him.

As usual, you can put some drugs in your hook tip to make things easier.

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It is a pretty instance process. 3 seconds may not be enough to stop a full sized human from getting free. – DonyorM Jan 22 at 12:40
@DonyorM Not enough time, but you can put a rat in a human size bag. Or broke him an arm. – JordiVilaplana Jan 22 at 12:42
If a shifter turns into a brook trout (good for spywork) and you thread a rope through the mouth and gill, he would be unable to change back since the human form does not have such an orifice. – JDługosz Jan 23 at 14:06

Use below freezing ropes or whips that when rapped around would freeze the cells and prevent transformation in that section.

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Jars. Lovely things-where peanut butter comes from. Anyhow, jars are very effective way to capture tiny animals if there is a lid. If you want breathing holes, either punch them in the top or make a space-oriented oxygen source that connects the inside of the jar to the real world.

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Essentially the magical form of a Faraday cage or net. As long as the creature is within the confines of the cage or the net then they are effectively prohibited.

Essentially a similar concept to the Ysalamir creatures in Star Wars EU trilogy Heir to the Empire, Dark Force Rising and Last Command, where said creatures project a natural bubble around themselves that blocks the force so that they cannot be hunted by Force sensitive predators.

Ysalamiri sink their claws into the Olbio trees on which they live and draw nutrients.It was very difficult to remove a ysalamir from its tree without killing it, Grand Admiral Thrawn used ysalamiri for defense by attaching them to a back harness or a nutrient frame which allowed him and his men to remain safely inside the ysalamiri's Force repelling bubble. He used this trick to accelerat the Spaarti cloning process without the usual side-effects which occurred when similar Force imprints interfered with one another.

Ysalamiri did not actually negate the Force; since all existence was infused with Force energy this would not be possible. Rather, they projected a bubble inside which users were unable to exert any influence over the Force. A single bubble measured up to 10 meters in diameter; large groups of ysalamiri could extend their collective bubble by kilometres, but only in great numbers.

A concept of this nature would suit a technological or medieval setting quite simply, just choose what the bubble that is projected negates.

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Welcome to the site! This is an interesting answer, but I think it's a little long and drawn out. I would narrow it down to the suggestion with accreditation to Star Wars. (something like "have a creature that stops the shapeshifting ability with a specific aura", along with a little more explanation. Ideally add how this is portable and easier than just carrying a largish-cage around. – DonyorM Jan 23 at 10:41

Assuming you know the person is a shifter:

"Shift or die!" See what form they take. If it's smaller than a human you put it in an appropriate net. If it's bigger you demand he shift back and then you put him in a human-sized net.

You'll need to carry a few sizes of net but not any huge amount. You'll also need a net made of metal to deal with gnawers.

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