A video captured the moment a strapping straphanger aboard a Los Angeles Expo train turned into a real-life Hulk and knocked out an unruly, shirtless man with a swift chokehold.

Warning: Video contains profanity.

In the two-minute video posted to YouTube, the shirtless man can be seen harassing passengers on the train in a threatening manner on Saturday night.

Suddenly, a commuter identified as Adrian Kaczmarek shows up and quickly puts the disorderly passenger in a chokehold.

Kaczmarek kept the man subdued and locked in the chokehold for close to 15 seconds before briefly knocking him unconscious to the floor of the train, the viral video shows.

“I was more concerned about my safety and the people on the train safety. I wasn’t sure if he had a knife or if he had a gun,” Kaczmarek told NBC Los Angeles.

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