a science-fiction story idea just popped into my head

Partly inspired by the movie "Brainstorm," in which scientists develop a machine that can record first-person experiences that can be played back—as experiences—by other people, I've thought of a story idea in which a team of people with backgrounds in AI, virtual reality, neuroscience, and other fields design a machine that allows you to experience the act of being beheaded... but without your actually being decapitated. What to call this machine? For public-branding purposes, maybe it could be called The Noggin Slicer, and going through the experience of decapitation could be called getting nogged.

Of course, it makes little sense for such a machine to provide so specific a virtual-reality experience (where, in this case, "virtual reality" includes internal sensations as much as externally originating "deliverances" of the senses), so the tech would have to evolve to provide all sorts of other bleeding-edge experiences. In terms of death and dying, those experiences could be terrifying things like being eaten by a shark or a tiger, being crushed by a steamroller, falling from the hundredth floor of a tall building, being dissolved in a tank of acid, being cruelly tortured, being forced to eat until one's stomach bursts, etc. But there would have to be more than death-related experiences for true thrill-seekers. Obvious ones would be experiencing the power and grandeur of flight, sampling a whole smorgasbord of peak/extreme sexual experiences, and so on.

There would be social implications. As with all cutting-edge tech, the rich would get first dibs before the tech democratized and filtered out into the regular populace, to the hoi polloi. Other social implications would be how people sorted themselves into thrill-seeking categories: the deathmongers, the sexmongers, the painmongers, the psychedelic weirdmongers, maybe even nerdmongers who enter the machine to force their brains to experience what it means to exist in mathematically higher dimensions than the unassisted brain can normally contemplate. Cliques, fan bases, and rugged individuals could all participate in whatever realities the machine can conjure.

And there's also the chance the machine can break down, maybe even in medias res. What would it be like to be blissfully flying through the heavens above the Rockies, when suddenly the machine glitches and smacks you back into reality? How would your mind and body respond to the jarring change? Would the change be as harmless as waking up from a dream, or something more severe and sinister?

And while we're on the topic of reactions, how would different people react to the same stimuli, e.g., to being beheaded? For some, it might be an amazing experience. For others, it might evoke horror and disgust. For still others, more fragile, it might be the final step off the cliff of psychosis. For my story, there would have to be legal implications.

Come to think of it, certain SF books have depicted something like the device I'm writing about. The pain box from Dune is a good example: young Paul Atreides is told to place his hand inside a mysterious box that begins to deliver a series of extremely dolorous sensations; the Reverend Mother administering the test of agony reminds Paul that he removes his hand on pain of death, so Paul has no choice but to keep his hand in the box and suffer the gauntlet of horrible sensations until the test is done. The pain box delivers experiences—qualia—directly to the mind. Meanwhile, the setup in "Brainstorm," starring Christopher Walken, is immersive, but the experiences come from real-life individuals (and, early in the film, from a chimp). There's never any mention made as to whether the device can be used to create experiences with no grounding in reality. My machine would be a fusion of the Dune pain box and the "Brainstorm" qualia device: all your senses would be fully engaged in a totally immersive-yet-fictive experience, even unto the point of death (although not beyond: in "Brainstorm," a character dies while recording her heart attack, and the recording of her death—which includes the voyage of her mind or soul to the afterlife—becomes a much-sought-after item for the rest of the film).

Anyway, it's just an idea. It needs refinement. Maybe I'll come back to it soon.