Dream species

Telepathic humanoid civilization in the Delta Quadrant. These people lived in a cave and their consciousness existed only in a dream state. For centuries, the dream species had suffered attacks from a variety of outsiders they referred to as the waking species. In order to protect themselves, the dream species took refuge in underground caverns. They established an artificial neurogenic field surrounding their planet, causing intruders from any waking species to fall asleep. Once in the realm of sleep, the dream species could deal with such intruders on their own terms.