Psychologically: If one dreams of comets, UFOs, fire rains of the sky, inexplicable phenomena and the landing of aliens, one might deal exceptionally often and intensely with such subjects. After C. G. Jung becomes a person by such dreams on a 'collective role' (in his existence) prepared. To whom this interpretation is too far-fetched: Maybe you are only one 'acts X' fan and cannot switch off 'simply' - not even in the dream. (See also comet, UFO)