A childhood belief about mirrors

When we were small, I convienced my little brother that our reflections in the mirror were our exact opposites and that they were all evil. His name is Sal so I told him that his reflection was named Las and that Las was an evil demon who would do him harm if he ever did anything to make him angry. A few weeks later we went on vacation and our hotel room had an entire wall that was one big mirror. Poor Sal was petrified and when my mom found out why she made me tell him the truth. However, I think he still believed that reflections were evil for sometime after that since I did see him run really fast past mirrors a few times after that.