On Friday, after Ben Carson passed him in the polls in Iowa, Donald Trump called his fellow candidate “super low energy.” Carson offered a response Sunday on NBC’s “Meet the Press” by referring to his violent past: “There was a time when I was very volatile.”

“As a teenager, I would go after people with rocks, and bricks, and baseball bats, and hammers,” he continued. “Of course, many people know the story when I was 14 and I tried to stab someone.”

In the unlikely event that you are one of the few people who don’t know this story, here’s how Carson summarized it in an interview with The Daily Caller last summer:

One of my friends angered me. And I just lunged at his abdomen with the knife. Probably would have seriously injured or killed him, but he happened to have on a large metal belt buckle under his clothing, upon which the blade broke.

And, of course, he fled in terror. But I was more horrified than he was, because I realized that I was trying to kill somebody over nothing—and that I would never realize my dreams of becoming a physician. And I would end up in jail, reform school, or the grave. And I just locked myself in the bathroom and started praying.

You wouldn’t like Ben Carson when he’s angry. Then again, you might not like him regardless!

“Fortunately, you know, my life has been changed,” he said Sunday. “I’m a very different person now.”

Photo credit: AP Images. Contact the author of this post: brendan.oconnor@gawker.com.