31  So,  the evil spirits  [in one of the men.  See Mark 5:1ff]  begged Jesus,  saying,  “If you are going to drive us out  [of this man],  send us away into that herd of  [wild]  hogs.” 
Matthew 8:31 Cross References - AUV
Mark 5:7
7  And shouting with a loud voice,  he said,  “What do you want with me,  Jesus,  Son of the Most High God?  I beg you,  in God’s name,  do not torture me.” 
Mark 5:12
12  The evil spirits begged Him,  saying,  “Send us into those  [wild] hogs,  so we can enter their bodies.” 
Luke 8:30-33
30  Then Jesus asked him,  “What is your name?” And he answered,  “ [My name is] ‘Legion’”  [Note:  This word means a number consisting of between 5,000 and 6,000],  for many evil spirits had entered the man. 
31  And the evil spirits begged Jesus not to require them to go away into the “pit”  [Note:  This appears to be the place reserved for the devil and his evil spirits.  See Rev.  9:1-11;  20:1-3]. 
32  Now a herd of many  [wild?] hogs was grazing on a  [nearby] mountain,  so the evil spirits begged Jesus to give them permission to enter  [the bodies of] the hogs.  So,  He gave them permission  [to do it]. 
33  Then the evil spirits went out of the man and entered the hogs.  The herd  [immediately] rushed down the cliff into the lake and was drowned. 
Revelation 12:12
12  So,  rejoice,  you heavens and you who live there.  It is too bad for the earth and for the ocean,  because the devil has gone down to you with great rage,  knowing that he has  [only]  a short time left.”