A Gamma Quadrant people who destroyed themselves in a power struggle, leaving behind a telepathic record that forced others to replay their final conflict.
The Saltah'na were a Gamma Quadrant people who died out in a bitter political struggle. They left behind telepathic energy spheres that recorded the conflict and could imprint it onto anyone who came near, compelling them to act out the same rivalry until it destroyed them as well.
In the episode Dramatis Personae, a Klingon ship returned from the Gamma Quadrant after its crew had turned on each other, and the energy matrix was released aboard Deep Space 9. Kira Nerys and others began plotting against Benjamin Sisko, who became distracted by building a clock. Odo, unaffected because of his changeling biology, worked out what was happening and destroyed the matrix before the crew could kill each other.