Astral Projection
Out of body experience
The experience of floating outside of, and in some cases, seeing one's physical body from a place outside one's body. This usually occurs spontaneously and is linked to dangerous circumstances, a dream-like state, a near-death experience, or use of psychedelic drugs. In this episode Dean tells Tessa that if they are having an out of body experience it means that they are spirits of people close to death. Other names for an out of body experience are bilocation, crisis apparitions, and fetches.
– Pad of Definitions (2.01 In My Time of Dying), Official Website
4.15 Death Takes a Holiday
Dean and Sam arrange an intentional out of body experience when they have psychic Pamela Barnes send them to the astral plane so that they can investigate their case. Once there, they are vulnerable to salt and iron, like ghosts.