What miracle had happened while the boys were at the party in Maniac Magee by Jerry Spinelli?

During the party in "Maniac Magee," a miracle occurred when Mars Bar Thompson, who was known for his bullying and tough attitude, became friends with Jeffrey Magee and even saved him from a dangerous situation. This unexpected act of kindness and friendship was considered a miracle because it showed a positive change in Mars Bar's behavior and attitude towards others.