Phobia shield

A Phobia shield is a device invented and deployed by the Galactic Council in order to protect worlds from robotic lifeforms like Cybertronians, creating physical projections of threats based on the target's greatest fears in order to drive them away, with the limitation of only being able to draw projections of the fears of conscious targets and fading when the subject providing the fear loses consciousness.

Fiction

2005 IDW continuity

On the planet Deimus, a Phobia shield was deployed by the Galactic Council to defend the world, driving off a Decepticon outpost at some point in the past. When an Autobot team consisting of Hoist, Perceptor, Swerve, Sunstreaker, and Bob landed on the planet, they fell under the influence of the shield, creating threats like Tarn, Metroplex, and Overmegasixwave from their minds. When only Hoist remained awake, his own fear of loneliness provided nothing for the phobia shield to project off of, providing a window for the Autobots to escape. The Waiting Game