Sonic grenade

Sonic grenades are United Nations Space Command weapons. Little is known about them, other than that several of these were used by Colonel James Ackerson in testing the MJOLNIR Mark V armor on Reach, hidden amongst the Pillars of Loki and used in conjunction with napalm grenades.

Theories
The sonic grenade may be similar to a Fragmentation Grenade in structure and detonation, except that it uses a miniature sonic boom rather than explosives. The grenade may be a non-lethal weapon used by drill instructors to teach Marines to keep their eyes peeled, hitting them with a loud sound that hurts their ears rather than actually causing them bodily harm. It would be one of the nicer booby traps used by DIs.

List of appearances

 * Halo: The Fall of Reach