ABC NewsBY: JACK ARNHOLZ

(WASHINGTON) -- In one of his first attacks on former Vice President Joe Biden's pick for vice-president, President Donald Trump criticized Sen. Kamala Harris as being “extraordinarily nasty” during the confirmation hearings for his then-Supreme Court nominee Brett Kavanaugh.

“She was nasty to a level that was just a horrible thing ... the way she treated now Justice Kavanaugh, and I won't forget that soon,” he told reporters Tuesday afternoon.

The forceful questioning by Harris, a former prosecutor, went viral on social media in the days after her exchange and it may be how she's best known to many Americans and it's a reason supporters say she will be a formidable opponent of both Trump and Vice President Mike Pence.

The California Democrat, who sits on the Senate Judiciary Committee, made a a splash when she asked Kavanaugh if he had discussed special counsel Robert Mueller's probe with any employees of a law firm run by Trump’s lawyer Marc Kassovitz.

“Well, is there a person you're talking about?” Kavanaugh asked Harris.

“I'm asking you a very direct question. Yes or no?” she responded.

After a continued back and forth, Kavanaugh told the senator, “I would like to know the person you're thinking of.”

“I think you're thinking of someone and you don't want to tell us,” Harris shot back.

But an exchange that gained even greater attention came when asked Kavanaugh about reproductive rights.

“Can you think of any laws that give government the power to make decisions about the male body?” she asked.

Kavanaugh froze for several seconds before responding, “I'm happy to answer a more specific question.”

“Male versus female,” Harris replied.

After a back and forth, Kavanaugh told Harris, “I'm not thinking of any right now, senator.”

The exchanges received considerable play on late-night talk shows and on social media.

Harris similarly garnered attention a year later during Attorney General William Barr’s hearing on the findings of Mueller’s report on Russian interference in the 2016 election.

When Harris asked if the president or anyone at the White House had ever asked or suggested that he open a Justice Department investigation into anyone, Barr, acting uncertain, at first repeated part of her question, "the president or anyone else..."

"It seems you'd remember something like that and be able to tell us," Harris said pointedly, implying he was being evasive.

“Yeah, but I’m trying to grapple with the word ‘suggest,’" Barr responded. "They have not asked me to open an investigation."

"Perhaps they suggested? Hinted? Inferred? Harris pressed him.

When Barr failed to finish his answer, she said, "You don't know," sarcastically.

Later, she asked Barr if he, Deputy Attorney General Rod Rosenstein or anyone in his office had questioned or reviewed the underlying evidence supporting the report's findings. Barr told Harris he had not.

Harris responded, expressing disbelief and questioning Barr's decision to accept charging recommendations without reviewing underlying evidence when making a "critical decision" about "the person who holds the highest office in the land and whether or not that person committed a crime."

"I think you've made it clear, sir, that you have not looked at the evidence and we can move on," Harris said.

ABC News' Soo Rin Kim contributed to this report.

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