As far as Myths and Legends about having TWO BODIES, stories about doppelgangers would probably be interesting for you. "Doppelganger" is a German word meaning "double walker". Some famous doppelganger stories are an old legend The Cemetery Mimic, also The Doppelganger of Beacon Hill Park, a story about the "haunted" public park in the city of Victoria, British Columbia; and an untitled story by Robert Dale Owen about Emilie Sagee. This original story was apparently told to him by Julie von Güldenstubbe, a daughter of a 17th century German Baron.Now as far as practicing ASTRAL PROJECTION a person does not have "two bodies" per-se. They have learned the ability to project their spiritual essence out of their corporeal body to travel to other places. The best non-fictional story of this is in the book The way of the Shaman, by Michael Harner, ©Copyright 1980 & 1990. Also Journeys out of the Body by Robert Monroe, ©Copyright 1971 & 1977, or Cosmic Journeys by Rosalind A.McNight, ©Copyright 1999, are both excellent.
When two fronts collide that have about the same temperature, wind might develop. When two fronts collide that have different temperatures, it can lead to a rain storm and sometimes tornadoes.