http://blog.wired.com/defense/2008/07/the-microwave-s.html

Literal:

The U.S. military bankrolled early development of a non-lethal microwave weapon that creates sound inside your head. But in the end, the gadget may be just as likely to wind up in shopping malls as on battlefields, as I report in New Scientist.

The project is known as MEDUSA – a contrived acronym for Mob Excess Deterrent Using Silent Audio. And it should not be confused with the Long Range Acoustic Device and similar gadgets which simply project sound. This one uses the so-called «microwave auditory effect»: a beam of microwaves is turned into sound by the interaction with your head. Nobody else can hear it unless they are in the beam as well.
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