A near-death experience is a personal experience associated with death or impending death. Have you ever had one, hopefully not!
I have not, but that sounds very scary.
They say there can be a feeling of detachment from the body, levitation, total peace, security, and/or the presence of light. 
I cannot even imagine how that would feel. what causes this?
They believe being that close to death comes from disturbed bodily multisensory integration. Basically the sensors in us are on overload 
That is so interesting. I hope I never experience that.
Near-death experience
A near-death experience (NDE) is a personal experience associated with death or impending death. When positive, such experiences may encompass a variety of sensations including detachment from the body, feelings of levitation, total serenity, security, warmth, the experience of absolute dissolution, and the presence of a light. When negative, such experiences may include sensations of torment and torture. NDEs are a recognized part of some transcendental and religious beliefs in an afterlife.
Different models have been described to
(AIDS). Novella wrote, "Denialists are pseudoskeptics—they pretend to apply the principles of skepticism (doubt) but they are dedicated to a final conclusion, and so they twist the process to their desired outcome."
- Near-death experience – A near-death experience (NDE) refers to personal experiences associated with impending death, encompassing multiple possible sensations including detachment from the body, feelings of levitation, total serenity, security, warmth, the experience of absolute dissolution, and the presence of a