An evil cellphone factory distributed cellphone units that can cause instant death to a human. It was distributed to every adults in this world.

The units will kill its owner by the ff reasons;

  • The phone died/destroyed.
  • Dismantling the phone.
  • The phone is not in the possession of its actual owner.

The units allows the owner to receive announcements from the factory and detect nearby owners.

Given these information the factory said they will trigger the instant death to everyone who owns the unit within a year and the only way to prevent this is to destroy half of the distributed units.

What can be the most realistic explanation on how will the phone kills its owner?

Edit: I am looking for a way that doesn't allow the owner to survive if the phone triggers its death killing procedure.

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    $\begingroup$ C-4 explosives in the phone. Guaranteed to succeed no matter which direction the person is and even if they are several feet from the phone. $\endgroup$ – cowlinator Jan 18 at 2:48
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    $\begingroup$ Stupendously excessive roaming charges. $\endgroup$ – user535733 Jan 18 at 3:00
  • $\begingroup$ Selfie challenge... based on statistics it is catching up to death by exploding battery $\endgroup$ – user6760 Jan 18 at 3:34
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    $\begingroup$ @cowlinator: Doesn't work unless you keep it a secret. If you know there's a chunk of C4 or similar in your phone, only the most seriously addicted will keep them. For a more realistic approach, just make them so addictive that people keep using them while driving, or are encouraged to take selfies with bears, or on the edge of steep drops... But that's already been done :-( $\endgroup$ – jamesqf Jan 18 at 4:19
  • $\begingroup$ @jamesqf the OP stuipulated it should "trigger the instant death to everyone who owns the unit". Your methods aren't instant and they won't affect everyone $\endgroup$ – cowlinator Jan 18 at 7:46

The easy way to achieve the different effects you want is by flipping the situation on its head.

Included with the cellphone is a tailored bug/virus/nanites aka "infection" that is reactive to very minor differences between phone transmissions.

Being within range of its transmission deactivates the problem.

  • The phone died/destroyed = no transmission
  • Dismantling the phone = subtly altering its transmission making it equivalent to
  • The phone is not in the possession of its actual owner = wrong (effectively no) transmission

If the "infection" is concentrated (perhaps for chemical or electrical nutrients) in the brain or spine, it might just be possible to save a few very lucky people through large medical intervention

The death would not be instant because the "infection" would need some short period of time, say an hour of feeling steadily worse, to continue its breeding to critical mass

This delay also lets you sidestep problems with the roll-out because the infection might need a few days to settle into its host. You need a way to sidestep the death trigger activating during the roll out (even if its only days or) or the 0.1% of initial adopters who throw it away die on day 1 and the CDC etc step in to find out why.

  • $\begingroup$ Welcome petera1289. Pretty good first post. Please take the tour and browse the help center at your leisure to get the hang of our rules. Enjoy the site. (From review). $\endgroup$ – BLT-Bub Jan 18 at 8:11
  • $\begingroup$ Rather than a virus, why not use a capsule with something lethal inside the targets body? They stop being around their phone long enough and it releases a toxin, acid or detonates an explosive around the C3/brainstem area. This means no lucky immunization or survival by lucky medical procedure. $\endgroup$ – Demigan Jan 18 at 9:53
  • The fact that this is a phone is irrelevant to the question.
    Unless the lethal effects happen as soon as the user has lost reception (in a tunnel, a basement, a rural area ...), your gadget has to function independently of the phone network.
  • Fail-Safe or Fail-Deadly?
    Phones can run out of power if they are not regularly recharged. Do you want this "dead" phone to kill anyway, with some backup battery for the kill switch? What if that runs out of power, too? Or does it kill just before it runs out of power?
  • "Possession" requires the gadget to guess intent.
    Am I "in possession" of my phone if it is in a coat pocket in the hall? Getting charged on my desk? Not in my hand while I'm taking a shower? You have to define the loss criteria better.
  • What if I have two phones, old and new?
    And if I carry sometimes one, sometimes the other? Can the new phone "in my possession" kill at a distance of a dozen miles or more?

One option I can think of is an implanted mind-machine interface which may be part of the latest fad in mobile computing devices. That might be fitted with a kill switch.

  • $\begingroup$ I also saw problems with the phone going dead, but this is a corporation that has no problem with doing a Thanos or killing off the entire population, so I expect that anyone who fails to charge their phone for whatever reason is simply seen as one less murder they have to worry about doing later on. $\endgroup$ – Demigan Jan 18 at 9:58

Whatever you use, you’re guaranteed to be discovered in short order.

A small amount of a non nitrate based explosive (to get past conventional bomb detection) and ball bearings that is detonated at the opportune moment when one of the conditions through a relatively simple program on the phone.


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