A few researchers in Japan have created a device that will “jam” someone’s speech from long range.
The device, when “fired” at someone, is supposed to literally get them to shut up.
Here’s how it works, according to Wired: the device has a directional microphone and speaker. When fired, it records someone’s speech, and then plays it back to them with a tiny delay of 200 milliseconds.
That appears to confuse the heck out of them and gets them to be quiet. Here’s a video of the device in action: