the microwave scream inside your skull

from danger room: 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.....

The effect has long been a laboratory curiosity, with no application. But, over the years, the military has been intrigued. The idea (dubbed "the telepathic ray gun") was mentioned in a 1998 US Army study, which turned up in a recent Freedom of Information Act document dump. Five years later, the Navy decided to put some R&D dollars into the project...

The directional beam could be used for targeted messages, such as in-store promotions. Sadovnik even suggests subliminal advertising, beaming information that is not consciously heard (a notion also spotted on the US Army's voice-to-skull page).