A Sleeper is a Virtual World participant who cannot leave the V-World. Sleepers are rumored to exist, but there are no verifiable cases of actual sleepers. Sleepers are named such since they supposedly have fallen asleep while wearing their holoband. More intense conditions of unconsciousness, such as a comatose state, may also manifest as sleeper participants.
Being a sleeper is apparently dangerous, perhaps since the condition of being virtually awake while wearing a holoband inhibits the body's ability to awaken itself in the real world. One may require external stimulation, such as a partner shaking the victim.
The holoband has a safety feature that automatically disconnects the participant. This may be a function of time, or perhaps it detects brainwave anomolies. ("There Is Another Sky")