Ghosts / phantasms
The universal experience of all exorcists, who have dedicated themselves to this subject, is to have observed that, once the distinction is clearly made between possession and infestation, there sometimes appears a third type of phenomenon, distinct from the other two: ghosts. Ghosts are apparitions of people who are in Purgatory. These apparitions have characteristics which are always the same and very different from infestations:
-the soul appears in human form.
-it does not say anything.
-it appears in a menacing and terrifying manner.
It never moves objects nor makes any noise. When it appears it just stares, in a very unfriendly way, and then just disappears. We know it is not the devil, because the phenomenon does not do anything more. It disappears if masses and prayers are said for its soul. These apparitions are ways of calling our attention so that prayers be said for it.