An astral body, or a spiritual body, is called upon when a djinn leaves his or her own body. It is a djinn's soul in its purest form that allows them to enter other people's dreams and gives them access to possess people. If their physical body gets destroyed, their astral form can enter into any human spirit and in turn, the host becomes the djinn's new body still retaining all the djinn's knowledge and personality.
The dangers involved in using the astral form is that the ghostly form cannot stay out of a body too long or it floats into space becoming a lost spirit. Plus, the spirit djinn can still be heard by other beings be they mundane or djinn, the spirit must avoid being exposed to cold air because the cold air will affect their astral form and make them semi-transparent enough to see.
When a djinn possess someone, the host maintains his or her original appearance and voice. While under possession, the host has no memory of whatever occurred while they were being possessed. One way to tell if someone is being possessed is the is a smell of sulfur in the air or if the lymph nodes in the throat is swollen. A djinn's spirit can be exorcised by the burning smell of a cat.