Summon Fear

Similar to Force Fear, summon fear was a dark side Force power conjured through Sith Magic, that caused the victim to experience their worst fears to the point of hysteria. It is a very powerful ability, and the duration and intensity vary depending on the caster. This spell is called upon when the caster moves their fingers in an intricate pattern, likely focusing the Force in a particular way, taking seconds to produce effects. The victim's deepest and most primal fears are made seemingly alive, often taking the form of demons or monsters that relentlessly torment the victim. The longer the spell is held, the more realistic and terrifying the illusions become. To an outside viewer, the victim may seem to suddenly seize and go insane. Depending on the spell's length, the effects could range greatly. Short durations could result in the victim waking up with only a small recollection of what happened. Longer applications can cause one's physical form to seize itself into unconsciousness, while the mind is virtually destroyed. The body remains effectively comatose, while whatever lasting consciousness is tortured for all eternity. Spells even longer endured could very well result in the victim's death.

This technique was believed to be lost until it was rediscovered by Darth Sirena.

Information courtesy of Wookiepedia