Qâzoi Kyantuska (translated as Suppress Thought in Basic and otherwise known as control mind) was a Sith magical ability that made the wielder effectively able to control and influence the minds of anyone they chose.
Employers of Qâzoi Kyantuska were capable of using the Force to telepathically dominate a single mind, or a multitude of individuals simultaneously. There did not appear to be any incantation or gestures required, as known users were shown to have simply been in the presence of their victims. The affected were seemingly in a trance, hypnotically paralyzed and unable to control their own faculties. Should the conjurer choose, the victim could end their own life against their own will. If the caster was in direct physical contact with an individual, they could tap directly into the individual's mind, and force them into whatever action they so desired.
Sith Acolyte Satal Keto displayed a physically taxing yet working mastery of mind control. With his power, Keto telepathically took command of his Krath chaos fighters and turned them into living weapons. These suicidal pilots all met their demise under Keto's hypnotic will, using their ships to crash into the opposing Republic forces.
Perhaps the most famous use of control mind was by the Dark Lord of the Sith Exar Kun. During the trial of fellow Sith Lord Ulic Qel-Droma, Kun stormed the hearing and mentally "froze" the entire assembly, except for Supreme Chancellor Sidrona and several others. Kun grabbed the Chancellor by his head, and when Kun's Sith amulet began to resonate with the dark side, the Chancellor's words were those of Kun—he was exerting his psychic control via direct physical contact. Sidrona was forced to preach Sith ideology, then when Kun was finished, he released his grip on the Chancellor, who then slumped down dead on the floor.
The Sith Emperor, also known as Tenebrae/Vitiate, was a prominent figure with one of the most potent manifestations of this ability. Vitiate utilized Qâzoi Kyantuska to dominate the will of influential individuals and bend them to his dark side agenda.
The Devaronian Cartariun found a Sith Temple on the planet Malrev IV where he stayed isolated for a number of years, learning to harness the power of the dark side through Sith magic. Though he eventually drove himself into madness, he gained enough knowledge of Sith magic to exert his will over the native Irrukiine. He was murdered however, by Girov Dza'tey who sought his dark power for himself.