Some visitations are from entities who no longer take physical form. Physical form was in the past for these entities, but they are spiritually evolved now, and take what would be called light form. The contactee is probably not aware of his contacts with these entities, unless in his dreams, which may or may not be consciously recalled. These entities have an extreme mental capacity, beyond what humans can endure. These entities have a force of love, also. Returning from a contact with these entities, the contactee feels as though he has risen from a warm bath into the cool air. He wishes to return to the warmth. He wishes this never to end. The contactee needs to bear in mind that what he desires is in his future. The entities in contact have also endured what the contactee is enduring, in their past. This is one of the reasons they have such an intensity of love for humans. Entities in light form appear to humans as balls of light, the strength of the light in proportion to the mass of the entity.
Human spirits are sensed, as ghosts, as a light cooling of the temperature or perhaps a visage of the human as it appeared during its last incarnation. This in no way relates to how the entity is shaped at present, but is an impression the formerly human spirit is giving to the human at the scene - I looked like this. Temperature changes are due to the disincarnate entity desiring to influence the scene, and being inexperienced at how to do this.
Wise and massive entities, almost invariably in the Service-to-Other orientation, appear as balls of light so their human contacts can mentally register their presence. Humans sense these entities well before they see them in light form, as the light form is assumed only as a type of dress to allow the human to better comprehend the situation. The contactee strongly senses someone in the room, or nearby, even though the contactee may be quite alone by all appearances. This sense that someone else is present is so strong that the contactee may actually glance around, disbelieving what their eyes are telling them. It is for this reason that these entities assume a light form, so that the contactee can relate to what is happening and get down to business.