Psi disrupter

"We've just received word from our research team that they've uncovered some kind of hidden weapons relay upon the planet Tarsonis. They report that it's called a Psi Disrupter, and that its purpose is somehow connected with the Zerg."

- UED Vice Admiral Alexei Stukov

The Psi Disrupter was developed by the Terran Confederacy to interfere with the zerg psionic link, fragmenting the Swarm's gestalt and rendering it less effective on the battlefield. At least one example of the Disrupter was constructed on Tarsonis but it was not activated during the zerg invasion. The nascent Terran Dominion attempted to locate the Disrupter but could not find it; it was thought lost.

The Disrupter survived the invasion of Tarsonis and was finally recovered by the United Earth Directorate Expeditionary Force, only to be slated for destruction by order of Admiral Gerard DuGalle. A local Confederate rebel leader, Samir Duran had convinced the admiral, above the objections of Vice-Admiral Alexei Stukov, that the Disrupter would undermine the UED's plan to enslave the Overmind. To prevent this Stukov dispatched his own troops to take over the "demolition" of the Disrupter, who secretly dismantled and shipped it to Braxis for reassembly.

Stukov's duplicity was soon discovered and a UED strike force led by Duran landed on Braxis with orders from DuGalle to not only destroy the Disrupter but execute the Vice Admiral as well. The strike force succeeded in mortally wounding Stukov but before dying he revealed Duran's treacherous nature and successfully appealed to the admiral to spare and use the Disrupter. Duran then attempted to destroy the device by activating the self-destruct, but UED troops were able to foil this attempt in time despite the sudden appearance of zerg forces. A UED garrison was deployed to safeguard the now-active Disrupter.

The Disrupter proved its worth in the ensuing UED assault and victory on Char. The second Overmind was captured and the UED began taking control of the Swarm in the sector, creating Slave Broods. The effects of the Disrupter were widespread and severely weakened Infested Kerrigan's control over her own broods.

Kerrigan rallied the sector's factions suspicious or hostile to the UED to her and, as a first step to ousting the invaders, led them on a strike against the Disrupter on Braxis. A small team led by Jim Raynor first destroyed a number of large external power generators feeding the Disrupter. With the Disrupter offline, Kerrigan used a psi-emitter provided by Arcturus Mengsk to reassert control over local zerg creatures, including a number of special zerg warriors, creating an army which was used to finally destroy the Disrupter.

Ultimately, the destruction of the Psi Disrupter and the death of the second Overmind would solidify Kerrigan's dominion over the Swarm.

StarCraft II
In StarCraft II: Wings of Liberty, a psi disrupter can be built, unlocked via 25 zerg research points. It decreases the movement speed of all zerg units.