Often we will hear "ghost stories" around the campfire, and for the most part these are fictional tales told to entertain children. However, sometimes they are real, as is the case of St. John Bosco and his friend Louis Comollo.
Bosco wrote about an encounter he had with the deceased Comollo in his Memoirs, an experience he never expected would happen.
God allowed such an encounter for a purpose, likely to remind Bosco of the reality of the afterlife and to urge him on in the practice of the faith. While we may never see a ghost in our lifetime, let us never doubt the existence of Heaven, Hell and Purgatory and live our lives as though they do exist.