Bernie Coombs (the author of All Creatures Do go to Heaven, which is published on our web site) and I have been chatting about what happened to the demons and the pigs in Mark 5:1-20.
My brief thoughts are:
Human beings seem to revel in their demons and in doing ungodly things. We are attracted by evil, and participate in many ungodly things.
The demons knew that Jesus wouldn't allow them to enter another human, so they suggested being allowed to enter the pigs. I believe Jesus allowed this to teach us and the demons a lesson.
Unlike humans, the pigs would rather die than be possessed by demons, so they rushed down the hill and drowned themselves in the water.
The pigs, being Godly (rejecting all aspects of demon influence), went with God. The demons went exactly where they didn't want Jesus to send them. Instead, they were sent there by the pigs whom they sought to harm.
I would very much appreciate hearing your thoughts.
In the Love of the Lord,