The only thing that handles a bully is someone bigger, stronger and scarier coming back at them.
I was a runt the first couple of years in high school. One day I helped one of the big football players when his car would not start. When we jumped his car from mine the end of the jumper cables looked like tweezers in his hand. The guy was huge. Eventually he went on to play pro football.
No long after this encounter I made the mistake of supposedly sitting in the wrong space in the boys locker room. One of the senior football players was a crazy bully. He was constantly harrassing the younger kids. Slapping them around and whatnot. When I sat in “his spot” in the locker room he picked me up and was about to toss me across the locker room when he screamed. I looked up and saw one very large hand I recognized. It was about to rip his hair out and another big hand was around his neck. The bully let me go and shortly after that was on the ground in a heap. My protector looked down at the bully, pointed to me and said “this is his spot!”. Then he looked around at all the other big guys standing around and said “ya’ll got that?”. They all nodded that they did. Except for the bully who was still on the ground with a size 16 cleated shoe on his neck. He was not about to move.
That bully gleered and sneered at me every time I saw him after that but he never touched me me again.
You stop bullies by doing what Ralphie did to Scut Farkus in "A Christmas Story."