My guy is 5 pounds and I swear he thinks he's Superman. His name is Maxwell Smart
Funnily enough I feel safer with him around than with my 110 pound black lab who will let anyone into our house who seems friendly and never barks at anything.
Min Pins are the same way. They think they can handle any dog that comes their way. We have a Great Dane/Lab cross in our neighborhood that Sugar is not the least bit afraid of ! She would chew of his ankle if she could just get to him . . . .