- "They mounted an ultrasonic disruptor in the tank? Clever... Its high-pitched broadcast was too high for us to hear but triggered our most basic instincts… leaving us terrified!"
- ―Obi-Wan Kenobi
The ultrasonic disruptor, colloquially known as the fear emitter, was a small device that could be used to broadcast high-pitched frequencies, triggering different physical and emotional responses in species such as Humans.
During the Clone Wars, General Grievous sent a detachment of battle droids to the moon of Gyndine and had them mount ultrasonic disruptors in their Armored Assault Tanks, for use against Galactic Republic forces there. The disruptors were programmed to trigger fear-related responses in the Republic clone troopers, thereby rendering them easily defeated.