My older brother decided to whip me one day when I was about 14 and he was 17. He did, so I got me a baseball bat and took the driver's side rear view mirror off his Corvair with it. Then a few dings to the hood. All while he was watching me.
"You want to beat on me some more, Brother?", I asked with the bat in my hand.
"No, not today."
That was the second to the last time he ever tried to beat me up.
The next time he tried, he was winning so I smashed my mother's (and her late mother's) antique wicker chair over his back, just like in an old cowboy movie.
He never tried to beat me up again, and we get along just fine now.