Somehow you managed to knock out an elemental shape-shifter. Where do you put it?

Elemental shape-shifter: A person who can change their body to the four classical elements: Earth (like the material), Fire (think Johnny Storm), Water and Air.

Assume that you are a multi-billionaire, and that you have access to any tech up to our current level.

Assume that you may have to visit the shape-shifter from time to time.

More info: the shape shifter requires magical energy to shift and stay shifted form, if out of magical energy the shift we return to human form to recharge or if unable it will go into hybridization until it can return to human form or gain enough magical energy to remain mobile in shifted form. magical energey is spirtual in nature and nothing you can do to directly block her access to it even send her into the vacuum of space wouldn't do it.

More info fire is the most powerful of the shape shifters form. It can generate theoretically generate the more magical energy. fire form requires the most amount of magical energy and the more hotter it gets the more energy she uses. She also can only recharge a very limited amount of energy outside of human form. So unless you imprision her right next to a magical super battery she is not going to go supper nova any time soon none the less you should probably make sure your prison is can withstand extreme temperatures, but should not have worry about her produce an more heat than a large forest fire.

Water: staying in water form require the second most amount of magical energy. in water form she can dissembled her body and control it's disassembled parts. however she can not control any water that did not originate from her and she requires all of her disassembled parts to rejoin before she can.

Air: less energy then water same rules apply

earth/rock. use a very low amount of magical energy she could easily stay in this form for days with out having to recharge.

She dose require food and drink while in human form. you also may have some questions for her to answer

  • 1
    $\begingroup$ What's the air and water do? $\endgroup$
    – Aify
    Dec 13, 2016 at 4:53
  • 1
    $\begingroup$ It depends on how they shape-shift. For instance, if they turn their entire body into water and reassemble it, they may need a watertight cell; if they simply become gelatinous, they may just need few pores. $\endgroup$
    – Zxyrra
    Dec 13, 2016 at 4:55
  • 2
    $\begingroup$ What exactly is each phase capable of? Is the air like a passive gas, or can it pummel the walls and break glass? Is the fire like a normal fire, or can it eject heated material and burn through metal? etc. $\endgroup$
    – Zxyrra
    Dec 13, 2016 at 4:57
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    $\begingroup$ This question is unanswerable if you don't specify the exact abilities this person has. Can the fire form attain any heat level and thus melt even tungsten? Can the air form flow through a crack in a material? $\endgroup$
    – Frostfyre
    Dec 13, 2016 at 13:20
  • 1
    $\begingroup$ Why can't you keep them unconscious? $\endgroup$
    – SRM
    Dec 13, 2016 at 15:28

7 Answers 7


Since you explicitly state that your shapeshifter requires food and water while in human form, presumably she requires oxygen as well. Just seal her in a steel box. Make sure the steel is thick enough so she won't be able to melt it. The limited amount of oxygen in her cell will force her to assume and maintain earthen form to avoid suffocation.

You can break the seals for an occasional visit/interrogation, at which time you can change the air as well. To maintain security during these visits, you might need to put her cell inside a yet larger steel box and seal the outer box before unsealing the inner box, but as a billionaire you can afford to keep a few welders on staff.

If you want to interrogate her personally, just get inside the outer box before they seal it. If you want to avoid physical contact entirely (I would), you could either set up a powerful speaker/microphone system, or simply etch a Morse code table on the inside of the inner box.

  • $\begingroup$ Or, even easier, just kidnap someone she cares about and hold them hostage. $\endgroup$ Dec 14, 2016 at 19:21
  • $\begingroup$ A lot like how Magneto was caged in the 2nd movie. $\endgroup$
    – RonJohn
    Apr 2, 2018 at 22:04

Use a Tungsten Vacuum Box, and keep it in space. Earth likely wont be able to break out of the box (Tungsten has ~1.7x the density of lead, and a really high tensile strength), Fire won't be able to melt it (and also will die out in a vacuum sealed box), water in 0G will just be forced into a sphere unable to do anything, and air, if he somehow escapes the box, will disperse into the vacuum, due to pressure difference, making it suicidal for him to try turning into air. If you really want to make it hard for him to get out, layer the box.

This answer assumes that magic handles the living requirements of the target.

Edit: Tungsten Vacuum Box with small magnets littered across the floor for communication. Use an airlock system in order to safely provide access to food and water. Don't forget to give her a space suit, and provide oxegyn refills once in a while (or spare suits via airlock). If she tries to get out, she'll likely destroy the only things keeping her alive.

  • 2
    $\begingroup$ Creative and safe but if they can turn into air and stay together in Earth's atmosphere (and have magic) I'm wondering if they could still stay together in a vacuum. $\endgroup$
    – Zxyrra
    Dec 13, 2016 at 5:45
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    $\begingroup$ This answer is overkill... I like it. $\endgroup$
    – Anketam
    Dec 13, 2016 at 11:07

A completely closed system is the safest while still being relatively cheap

A closed system is a system in which energy can enter and leave, but matter cannot. If you allow matter in and out, there is more of a risk of escape (turning into air and flying into the ducts, etc), but energy should be safe (the lights, etc)

Food and Water

Design the facility with self-sustaining farms and water tanks. Water can be recycled from the air and from waste after it's been released; food waste can become fertilizer through automatic processes. It's not nice, but it's worth a try. Alternatively, have a lifetime-supply of fertilizer already in place, in a container; have machines do the farming for the elemental too.


All electricity used to power devices within the complex should be passed as radiation through a 1-meter thick layer of the strongest possible glass, then converted back into electricity; this eliminates ducts that could be used for escape as a gas or liquid.

Air circulation

This can be moderated by a device inside the compound. Use reduced oxygen levels, to limit the elemental's fire ability; consider also lacing the air with rohypnol or another significantly active drug that can preserve consciousness in low doses while inhibiting memory and decision making.

Walls, floors, and ceilings

These should be airtight, watertight, fully sealed materials; additional layers of padding would be ideal to prevent self-harm, as it's hard to intervene with a closed system from the outside. Beneath these layers, place one meter of steel, one meter of lead, and five of concrete. For good measure.


While space is theoretically the most secure location to use, the air elemental stage may be a significant problem. If the creature can keep itself together in a gaseous state, it can likely survive in space long enough to make it back into the atmosphere of Earth - combining this with its fire capabilities, heat provided by ionizing radiation will also be insigificant.
Therefore, you can manage on Earth, where it's cheaper, and you can still view it. Perhaps underground.

Additional Security


  • Multiple layers - closed systems inside closed systems
  • Thorough video surveillance
  • Surrounding each layer of concrete with a mesh of live wires; these will stun the elemental, and, if they break, the resulting loss of electricity will alert security teams
  • Releasing an additional drug into the facility's air system if anything is amiss, inducing coma if possible
  • Lowering the temperature or even freezing the facility as fast as possible if anything is amiss (even the fire part will be put out)


Can be done safetly through security cameras or thick glass.


Keep her in separate boxes

she requires all of her disassembled parts to rejoin before she can.

She also can only recharge a very limited amount of energy outside of human form.

So keep her as an element, but divide her into two boxes. Because her element is not all together, she can't go back to human form. Being outside her human form, she can only get a "very limited amount of energy", and is no longer a threat.

Any airtight box should do for air, earth, water. She probably wont take a fire state as she doesn't have the energy. If she does, fill the box with water—without oxygen the fire can't exist.

If you want to interrogate her human form, she should be very weakened from being forced to remain in a energy-draining state, so won't be much of a problem.

How to make her go back to element form? Put her in a box that slowly grows smaller until she's forced to change shape.


Simplest answer?

Drugs. Keep your shape shifter heavily sedated (or in an induced coma) and fed through a tube. It's easy, cheap and doesn't take up much space. If you need to talk to them you can slowly wake them up while keeping them on a cocktail of drugs that keeps them happy and compliant, so much so that they won't even consider the need to shape shift. Another option is to create a proprietary drug that's hugely addictive and has a short lifespan. Soon they'll be your willing slave, as long as they can have one more hit. As long as you keep the supply limited and the shifter doesn't know how the drug is made they're your personal puppet.

If you want a slightly more vicious option: A shock (or explosive, depending on how the 'magic' works) collar that has electrodes embedded in the person's throat and spring loaded pressure sensors pressed against the skin. If the resistivity changes it goes off. If the pressure changes it goes off. If they stray too far outside a pre prescribed area it goes off. As long as the transformation isn't completely instantaneous and the shape shifter is still vulnerable to being killed/paralysed while human (or even if they can be convinced that they are) they can't shape shift without dying or searing electrical agony. This has three big advantages:

1: You can put them in a silk prison. Give them a garden and a nice house, just make sure they know that going past the petunias means searing electrical agony and/or death. This makes extreme actions (like trying to escape) less likely. Heck, you can even organise day trips if you really want to.

2: They're easy to access. You want to talk? Ok. Talk. Oh, and if you don't answer my questions then there's always searing electrical agony.

3: They can't get away. The prison is pretty much built into them. And any disobedience means... you get the picture.

The downside is that you'd need to keep the collar charged. That's easily doable with prison guards, or if you just want to keep them contained you can leash them to the wall with a power cord.

So basically: Don't try to make a prison. Just make sure the shifter wont do anything you don't want them to, then tell them to stay still.

  • $\begingroup$ good answer but their are some problems, a electric collar wouldn't work on the Rock or water form an explosive collar wouldn't work on the fire form or water form. Would be too easy to have her turn to water and slip the color right off. $\endgroup$ Dec 14, 2016 at 21:46
  • $\begingroup$ Drugs might work though it would be risky and dangerous but if you were just cazy enough to do it, it might work $\endgroup$ Dec 14, 2016 at 21:48
  • $\begingroup$ @BryanMcClure: That's why the time it takes to transform is important. If she's transforming then she's still vulnerable, if the transformation is instant then she's not. If you can convince her that the collar will kill her anyway then it really doesn't matter if it will or not: She isn't going to risk it. $\endgroup$
    – Joe Bloggs
    Dec 15, 2016 at 8:54

Got an enchanter around?

I couldn't say how many jerk kings, rich folk, etc have captured a character and slapped some manacles of Anti-magic Field on me.

Using DnD 3.5 item creation charts, it would only cost them 198,000 gold. If gold were at 1,800 per ounce, the price tag means a little over $114 million... assuming we can scale the economy in this way.

$114 million for each person is expensive but works on ANY magical prisoner. You also don't have to user manacles per se since it works at a 10 ft distance.

How much do you care about their power?

Make them forget they have any powers or how to access them. Lobotomy may be a nice permanent fix.

You also may use psychosis, drugs or a combination to affect their memory or suppress their powers.


Make a solid, water tight, fireproof box with an air tight lid.
Balance the box in such a way that if the weight inside changes even a little the lid slams shut, sealing the air in.


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