Psi-emitter

The psi emitter (also known as a Transplanar Psionic Waveform Emitter) is a piece of Terran technology in the StarCraft universe. It emits the psionic "signature" of a Terran Ghost or other such psychic at interplanetary distances, and can attract the attention of the psi-sensitive Zerg.

It was used by the Sons of Korhal rebel group, led by Arcturus Mengsk, and possibly the Terran Confederacy as a secret weapon to lure Zerg towards targets of their choosing. The technology was discovered by the Sons of Korhal after they raided the Jacobs Installation upon the Confederate world of Mar Sara, and it was believed by the Sons of Korhal to have been intentionally used to draw the Zerg to the planet. It was later used upon Antiga Prime and Tarsonis against Confederate garrisons upon those worlds.

In StarCraft: Brood War Episode VI Arcturus Mengsk was deposed by the United Earth Directorate and forced to seek "refuge" with his former enemies, Jim Raynor and Infested Kerrigan, yet still had access to this technology.

The technology was instrumental in the decisive defeat of the UED forces on Braxis, as the psi-emitter lured Zerg into Kerrigan's control, and were then used to defeat the UED forces.