My eight year old grandson had an encounter with a child who has been agressive before. This child punched my grandson in the eye. They were at a beach party and the children were all racing around when suddenly this boy attacked my grandson. To top this off, the boy's father pulled my grandson's shoulder and started a tirade agains him. Everything got sorted out, but this is the second unprovoked attack by this child who has displayed aggressive behavior on several other occasions. How should this be handled?