It is perhaps no surprise that amid a campaign that has become all about Donald Trump, Thursday night’s Republican debate was also all about the real estate mogul.

The frontrunner for the Republican presidential nomination took incoming fire from his rivals and dished out attacks. He was forced, by Marco Rubio, Ted Cruz and the Fox News moderators to defend his record, most notably the controversy over Trump University.

In his responses, Trump dismissed Rubio as “little Marco” and Cruz and “lying Ted.”

Ohio Gov. John Kasich, meanwhile, tried to stay above the fray.

“Throughout this campaign, I have talked about issues,” he said. “I have never tried to go and get into these kind of scrums that we are seeing here on the stage and people say wherever I go, ‘you seem to be the adult on the stage.’”

At one point, during a heated exchange between Trump and Rubio, Cruz interjected a question: “Is this the debate you want playing out in the general election?”

Nevertheless, as the debate concluded and Cruz, Kasich and Rubio were all asked whether they would support Trump if he were the nominee, all three said yes.

Here are five moments that mattered at the GOP debate in Detroit:

1. Trump Gets Vulgar

Near the beginning of the debate, Rubio was asked about his decision to personally attack Trump, when he said previously he would not.

Rubio said he would rather have a policy debate rather than a personal-insult fest, and Trump agreed saying of Rubio, "He's really not much of a lightweight.”

Then, talking about Rubio’s insults, the debate went vulgar: “And he referred to my hands if they are small, something else must be small. I guarantee you there is no problem. I guarantee you.”

2. Trump and Kelly Meet Again

“Mr. Trump, Hi. How are you doing?"

These were moderator Megyn Kelly’s first in-person words to Trump on a debate stage since last August after Trump refused to participate in the most recent Fox News debate.

“Hello. Nice to be with you, Megyn,” Trump said. “You’re looking well, you’re looking well.”

She asked whether Trump would release off-the-record comments made to the New York Times about immigration. “I would never release off-the-record conversations,” he said. “I don't think it's fair, frankly, to do that to anybody.”

Ted Cruz and Marco Rubio insisted it was up to only Trump -- not the newspaper -- whether the comments would be released.

3. Trump Flip-Flops on Visas For Highly-Skilled Workers

Kelly confronted Trump over immigration, asking why his website says the GOP frontrunner is against more visas for highly skilled workers while at the CNBC debate he said he was in favor of more of these types of visas. Trump immediately flipped:

“I'm changing,” Trump said. “I’m changing. We need highly skilled people in this country. If we can't do it, we will get them in. And we do need in Silicon Valley we absolutely have to have, so we do need highly skilled. One of the biggest problems we have is people will go to the best colleges, they will go to Harvard, to Stanford, to Wharton, as soon as they are finished they get shoved out. They want to stay in this country. They want to stay here desperately. They are not able to stay here. For that purpose, we absolutely have to be able to keep the brain power in this country.”

Kelly pointed out Trump was “abandoning the position on your website.”

Trump answered, “I'm changing it and I'm softening the position because we have to have talented people in this country.”

Kelly moved onto the Buzzfeed report earlier this week that said the New York Times has the transcript of an off-the-record conversation the newspaper had with Trump where he reportedly indicated a more flexible on the issue of immigration.

Trump said he would not allow the paper to release the conversation: “No. I never do that.”

4. Trump University Under Fire

Trump University, which is the subject of litigation for alleged fraud, grabbed the spotlight in a clash on the debate stage between Rubio and the real estate mogul.

Trump asserted the school had an “A” rating from the Better Business Bureau and students were happy with the course.

But Rubio and moderator Kelly hit back, saying that the last public rating was a “D-.” “It was the result of a number of complaints they had received,” said Kelly.

“You were willing to say whatever you had to say to get them to give you their money,” Rubio said. “When they realized what a scam it was, they asked for their money back and refused to give their money back.”

In a statement, the BBB said that Trump University's rating fluctuated between an A+ and a D-. Trump University changed its name in 2010 after the New York State Education Department demanded it remove "university" from the name.

Trump has repeatedly denied the fraud accusations in court papers and on the campaign trail, insisting tonight that he will win the case.

5.Yoga Time

It was more schoolyard taunts, a common theme throughout the debate. Cruz said Trump has a “tenuous relationship with the truth,” and Trump kept trying to interrupt him.

“Donald, please, I know it's hard not to interrupt. Try,” Cruz said.

He kept interrupting and Cruz tried a different tactic: “Breathe, breathe, breathe.”

“I am, Ted,” Trump answered.

“You can do it,” Cruz snapped back. “You can breathe. I know it's hard. I know it's hard.”

Rubio then jumped in: When they're done with the yoga, can I answer a question?”

Cruz ended the back and forth saying, “You cannot, in fact, care about conservative Supreme Court justices and support Jimmy Carter for president. You cannot care about conservative Supreme Court justices and support John Kerry.”