Painless, Undetectable Laser Injection
The best way to assassinate someone is to make it look like it's not an assassination at all. So good news, ninja of the future: The mad geniuses as MIT have created the hypospray from Star Trek. MIT's device pushes a "near-supersonic dose of medication straight through your skin into your body." The drugs are fired through the flesh on a blast of air smaller than the proboscis of a mosquito.
It's painless, doesn't leave a mark, and apparently you can unload this thing right into someone's eyeball or eardrum without any ill effects. All you need to do is bump into someone and BOOM. Faster than you can dramatically announce, "Hail HYDRA," rattlesnake venom is coursing into your victim's bloodstream.
Or, in a more likely application, a heavy dose of Viagra while your buddy is on a first date.
But with these types of devices, it can be hard to control the dosage and the potential for residual splash back. If you need a specific amount of chemicals to go to an exact depth in the flesh, then what you need is a laser needle. Scientists in South Korea have developed a laser-driven microjet injector that can launch a laser stream of medicine (or poison) directly into your body with precision.
Optics Letters via Science Daily
Explained here with this ... well, look, it's just dangerous.
The beam is about the size of a human hair, it's extremely accurate, and -- like any supervillain tech worth its salt -- it's a laser. Currently, the injector has to be pressed close to the skin, but a little more sinister R&D, we could be looking at a short-range injection gun. Assassins the world over will be able to shoot invisible, painless beams of toxins into their doomed targets at will. Also, babies won't cry so much when they get their shots! There's a silver lining to everything!
For more tips on supervillainy (or stamp collecting), check out Monte's blog.
For more weapons that are better suited for fiction, check out 6 New Weapons That Are Making War Look Like a Cartoon and 7 WTF Military Weapons You Won't Believe They Actually Built.