Revelation 12:12says the devil has great anger, because he knows he has but a short time left. Listen carefully. If the devil tried to deceive people about Jesus' first coming, you can be certain he's going to try to confuse all Christians about Jesus' second coming. He wants them to believe something that is not Biblical, so they're not ready to meet Jesus when He comes.
Jesus in His love foresaw there would be much deception about His second coming. He personally gave us two great warnings that we should look out for to make sure we're not deceived. Matthew 24:24.