The devil exists. While we are not to give him more acknowledgement than necessary, we must be aware of his existence and the dangers he presents to us.Are there non-demonic ghosts?
The Church teaches that distressed souls from purgatory can with God's permission appear for prayers.
Patrick Madrid & Fr. Carlos Martin on the devil:
http://ihrarchive.org/archive/rhrn-20131112.mp3
Prayer to St. Michael
