Alright kiddo, so there was a guy named Bar-Jesus in the Bible. Bar-Jesus means "son of Jesus" but it doesn't mean Jesus Christ who we talk about a lot.
So, Bar-Jesus was a sorcerer and a false prophet who tried to stop Paul and Barnabas from sharing the good news about Jesus. But Paul, who was filled with the Holy Spirit, called him out and said "You are a child of the devil!" Then, Bar-Jesus was blinded and people were amazed at the power of God.
Basically, Bar-Jesus was a bad guy who got in the way of people sharing the message of Jesus and God put him in his place.