Theres a device which can project sound into peoples skulls or localized areas. Its commonly used at nerdy geeky conventions like Sigraf since like 1999 for lulz and advertisement.
Some crazy fucks think the government is actually investing in this shit to drive people over the edge and create false flags or manipulate them to do their bidding.
http://www.technologyreview.com/feat...the-sound-war/
Been around for fucking ever.