Video from Capturing Christianity
"In this short clip, Father Vince Lampert recounts several real-life examples of exorcisms that he's personally been part of. We also discuss what else could have been going on if not demon possession. Link to the full interview: https://youtu.be/nhhi7Fk3ueI " from video introduction.
Father Lampert speaks to the manifestations of theses entities which are exhibited to instill fear in the person possessed and those watching. Also He points out that all of these possessions are within the permission and providence of God. As to why theses entities do what they do Father Lampert states that they are trying to mimic god in every way including God the Son's incarnation in a human body. Lampert also speaks to the mechanics of a Demon possession.