The Rwasundi are a rare species of humanoid demons whose presence in our dimension could cause Localized Temporal Disturbances. If a human was affected by said disturbances, they would experience vivid hallucinations as human perception is based on linear chronology. A trio of these demons were summoned by Andrew Wells as part of the Trio's plot to frame Buffy Summers for the murder of Katrina Silber at the hands of Warren Mears, the Trio using the temporal distortions to create the impression that Katrina had been killed when she wandered into the fight and Buffy struck her by accident.