Needles are scary, so in the spirit of medical advancement, a lot of Science Fiction portrays future doctors instead delivering Magic Antidote, Instant Sedation, etc. to patients via a gun-like jet injector
— also often referred as a "hypospray" ever since Star Trek: The Original Series had popularized that name.
In a darker application, jet injectors are also used in some sci-fi works to insert microscopic explosives into a victim's neck for the purposes of Explosive Leash, Why Am I Ticking?, and/or Your Head A-Splode.
Jet injectors are a Real Life technology and a functional alternative to classical syringes, but their mass adoption is hampered mainly by the issues of proper disinfection (both of the device, and of the open puncture wounds it produces) — how future medicine will solve this problem is usually Hand Waved in fiction. Also, while RL jet injectors are primarily applied to the patient's arm to deliver medicine into their muscles, fictional hyposprays are often jabbed right into the neck, implying an intravenous or intraarterial injection. Sometimes, they can even do so right through the patient's clothes — never mind the even greater sanitary problems posed by dirty and/or sweaty clothing.
Examples:
- Sword Art Online: The Arc Villain his allies of the "Phantom Bullet" Arc uses a needleless injector to kill their player victims IRL as he simultaneously kills their avatar by shooting them.
- The Andromeda Strain. When the members of the Wildfire team are undergoing decontamination procedures to enter the facility, they receive an automatic injection by a futuristic pistol-like jet injector device.
- Escape from New York: To keep Snake Plisskin from escaping once he's loose, a gun-like jet injector is used to insert a miniature explosive device into his neck. If it isn't removed within 24 hours, it will kill him.
- Flash Gordon: The title character is treated to one of these following the encounter with the Wood Beast. While recovering from its sting, Flash has a gun-like injector that has a green ball in place of a needle pressed to the outside of his arm (rather than the inside, close to the vein). It makes a sharp "hiss" implying that it works like a hypospray.
- The Running Man: While being prepped to appear in the title game show, Ben Richards has an unknown drug infused into him by a gun-like jet injector.
- Suicide Squad (2016): Each member of the Squad has a nanite explosive placed in their neck with a gun-like jet injector. This is so they can be killed if they try to escape or disobey orders during the mission.
- Total Recall (1990): While Douglas Quaid is at Rekall to get a memory implant, he is given a relaxant in a gun-type jet injector to make it easier for the implantation to occur. When Quaid later goes berserk, he is repeatedly injected in the leg with the same injector to render him unconscious.
- Isaac Asimov's The Naked Sun mentions a "high-pressure needle jet" as an alternative to hypodermic needles.
- Star Wars Legends: While not appearing in the original movies or in the reboot continuity, hyposprays had shown up in multiple EU novels.
- In Jack Vance's 1956 sci-fi novel To Live Forever, devices called hyposprays are used for drug injection.
- Vorkosigan Saga: Hyposprays (specifically referred to as such in the books) seem to have mostly taken the place of syringes, used to administer everything from routine medication to doses of Truth Serum. Considering that the series has a few roots in Star Trek fanfiction, it's easy to see where this came from.
- Farscape used Off-the-Shelf FX in the form of a laboratory pipette (which the average audience member would not be familiar with) with the usual hiss sound dubbed on.
- The Man from U.N.C.L.E.: Hyposprays are mentioned in the Universe Compendium The Dagger Affair.
- Mission: Impossible: Rollin Hand and Dr. Selby mention hyposprays as early as S1E24.
- Red Dwarf: Episodes such as "Quarantine" feature Kryten using a handheld injector device to treat Lister.
- Star Trek's hyposprays are likely the Trope Codifier. As early as the original series, they have been used by doctors to deliver various medicines (conveniently packaged in easy-to-insert capsules) to patients in adjustable doses. Regarding application through clothes, the franchise has been inconsistent: sometimes people would be injected right through their clothing, other times medical staff were shown removing it to expose skin before using the hypospray.
- In Cyberpunk, the jet injection technology is directly inspired by Star Trek to the point that the injection devices have the street nickname of "Bones McCoy".
- Scum and Villainy, being inspired by every single Space Opera and Space Western ever published, naturally includes "spray hypos" in the Fine Medkit belonging to the Stitch playbook.
- Cyberpunk 2077: Gun-like jet injectors appear to be ubiquitous in the Night City, particularly with ripperdocs like Viktor, who uses one early in the game to sedate V's right arm while he grafts a ballistic augmentation onto their palm.
- Killing Floor calls its healing item a "Medical Syringe" but its design is clearly a modernized take on the classic jet injector gun, complete with pressure bottle and medical vial. Also notable in that the player injects it right through their clothes and into their wrist, both of which are generally considered to be a bad ideas with a jet injector.
- Oni: Hypo sprays serve as common Health Potion pickups.
- Star Wars: The Old Republic: Hyposprays have been introduced as lootable and usable items in patch 2.0.0, specifically for the purpose of injecting isotope-5 trace elements.
