I've often wondered why Jesus sent Legion into the herd of pigs. Lots of obvious things have come to mind for a while - it shows the size of the demonic force just defeated for one.
Thinking about the Exodus made me wonder. God destroyed the Egyptian army by plunging them into the sea in Exodus 14. Jesus destroyed a demonic army by plunging them into the sea in Mark 5. Co-incidence, or is Mark teaching us that because of Jesus' crucifixion those demons "whom you see today you shall never see again" (Exodus 14:13)?