What are Out-Of-Body-Experiences (OOBE's)?
OOBE's are real. The experience is real. Sometimes when a person is under an unusually extreme amount of stress (like when in mortal danger or after a serious injury) the mind experiences itself as if it were outside of, detached from, the bag of meat that is the body. This dissociative affect is the result of the brain being flooded with chemicals which make dealing with the unbearable, bearable. The affect can be duplicated by taking dissociative drugs such as ketamine.
Before we had rational explanations, the illusion of being outside of the body was believed to be a veridical occurrence. Of course, plenty of smart people still think that we do have a soul that can exist separate from the body, and that these OOBE's are not illusions. That's a decision you have to make.
There are also dreams that can resemble Out-Of-Body-Experiences. This is in the realm shared by false-awakenings and astral projections, all of these dreamy phenomena feeling very realistic while they are happening. They also tend to feel a little creepy, or very creepy as with sleep-paralysis. The only thing that really differs between these phenomena and lucid dreaming is that the former do not include realization that a dream is the answer (question = where am I?).