Astral projection

Astral projection is the meditative process of creative visualization by which the soul travels beyond the body to other locations without first undergoing death. The body remains alive through a shining, narrow silver cord that forms a connection between it and the soul. A soul traveling in this manner is aware of its surroundings and can move freely, as in a lucid dream. Experienced souls are able to travel to any location on any plane, and particularly powerful ones can even affect their physical surroundings.

Because the life of the body is sustained by its connection with the soul, it will die instantly if the silver cord is severed. For this reason, those undergoing astral projection ward their silver cords with powerful spells and keep all their senses trained on their surroundings, lest some prowling fiend sever it to claim its tethered prize. The silver swords of the Githyanki are also capable of cutting the silver cords of astrally-projecting travelers - a frightful thought, given that all trans-planar astral projection crosses through their native Astral Plane.