In an election rally in Iowa on Thursday, Donald Trump went off on an epic 9-minute rant against retired neurosurgeon, Ben Carson. In a report by The Huffington Post, Trump referred to his rival as an "enigma."

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"Carson's an enigma. He wrote a book, and he's doing great in Iowa. He's second in the polls. With all these professional politicians, I'm first, Carson's second, and I don't understand it, I really don't understand it. Because he wrote a book and in the book he said terrible things about himself. He said that he's pathological and that he's got basically pathological disease. Now he wrote this, I guess before he was running for office or thought that he was running for office, and I don't want a person that's got pathological disease. I don't want it," he said.

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Trump even reenacted Carson's alleged attempt to stab a friend during the days of his youth.

And we thought this election rally couldn't get more interesting.

Watch the full meltdown below.

Tags: donald trump Ben Carson presidential election