Rhak-skuri, also known as "Dream Singer" in the ancient Sith tongue, constituted a dark side corrupted offshoot of the Diplura family. These creatures were native to the planet of Upekzar. These insect-like rhak-skuri secreted potent pheromones. These pheromones could trigger intense and frightening hallucinations in mammalian species. They sustained themselves by consuming flesh, and also by consuming the fear generated in their prey, which included Force-sensitives.