Las Vegas, Nevada (CNN) Michael Bloomberg 's billions got him onto the debate stage -- but did nothing to spare him from the barrage he faced Wednesday night here in Las Vegas .

In the most fiery and contentious Democratic primary debate yet , Massachusetts Sen. Elizabeth Warren led a non-stop barrage against the former New York City mayor who was appearing on stage for the first time. She kicked it off by calling him an "arrogant billionaire" who "calls women fat broads and horse faced lesbians."

Then everyone else jumped in.

Minnesota Sen. Amy Klobuchar accused Bloomberg of "hiding behind his TV ads." Former Vice President Joe Biden hammered him for opposing Obamacare. Vermont Sen. Bernie Sanders attacked Bloomberg's support for stop-and-frisk policing in his first answer of the night. Former South Bend, Indiana, Mayor Pete Buttigieg called him "a billionaire who thinks that money ought to be the root of all power."

The pile-on against Bloomberg came three days before the Nevada caucuses, as candidates trailing Sanders and with nowhere near Bloomberg's money are desperate to prove they deserve to remain in the race as it narrows.

Here are six takeaways from the ninth Democratic presidential debate:

Bloomberg's bad night

Bloomberg arrives for the ninth Democratic primary debate

Democratic voters have been laser-focused on electability -- and Bloomberg's willingness to spend hundreds of millions of dollars on an advertising campaign had lent him the perception of it in recent weeks, as he's jumped into double digits in national polls. That perception might have been shattered Wednesday night.

Bloomberg had answers for none of the criticism about his previous support for stop-and-frisk policing, his opposition to Obamacare, offensive remarks about women or why he hasn't yet released his tax returns.

His worst moment came when Warren and Biden challenged him to release women who alleged sexism and misogynistic behavior by Bloomberg and at his company from non-disclosure agreements. Warren said those women were "being muzzled" and that "the drip, drip, drip of stories of women saying they have been harassed and discriminated against" would be a massive liability in a general election.

But Bloomberg didn't address any of their criticisms, and wouldn't budge.

"None of them accuse me of doing anything other than, maybe they didn't like a joke I told," Bloomberg said.

"I'm simply not going to end these agreements because they were made consensually and they have every right to expect they will stay private," he added.

Warren lights the stage on fire

Warren gestures as she speaks during the ninth Democratic primary debate

Desperate for a return to the spotlight after disappointing finishes in Iowa and New Hampshire, Warren installed herself as the leading attacker in the debate's opening minutes. She eviscerated Bloomberg's deflection on a question about allegations of misogynistic behavior at his company after he highlighted female executives there and at his philanthropy.

"I hope you heard what his defense was: I've been nice to some women," she said. "That just doesn't cut it."

And while Bloomberg got the worst of it, Warren spent the whole night on offense.

In a single, memorable answer, Warren lambasted three of her opponents' health care plans. She called Buttigieg's proposal "a slogan that was thought up by his consultants." Klobuchar's, she said, was "like a Post-It note." And she said Sanders' "Medicare for All" plan -- which Warren largely backs -- is hurt because "his campaign relentlessly attacks everyone who asks a question or tries to fill in details about how to actually make this work."

The front-runner is largely unscathed

Sanders speaks between Warren and Biden during the Democratic presidential primary debate.

For the first time in this long primary campaign, Sanders took the debate stage as its national front-runner. But unlike others who have held that unofficial mantle, and carried the target that comes with it, Sanders emerged from the experience mostly unscathed.

The Vermont senator faced familiar lines of attack -- that his democratic socialism makes him unelectable and that his Medicare for All plan is unpractical -- but Bloomberg's presence altered the dynamics of the debate enough that Sanders was able to stick to his message and avoid being dragged into deeper waters by his rivals.

Bloomberg also gave Sanders a fresh target: a real, live billionaire onstage to hammer when he spoke about income inequality.

"Mike Bloomberg owns more wealth than the bottom 125 million Americans," Sanders said at one point. "That's wrong, that's immoral, that should not be the case when we got a half a million people sleeping out on the streets, when we kids who cannot afford to go to college, when we have 45 million people dealing with student debt."

Buttigieg urges Democrats to 'wake up'

Buttigieg speaks during the Democratic presidential primary debate

Buttigieg came into the debate focused on denting the front-runner, Sanders, while offering himself as a cogent moderate alternative to Bloomberg. And in moments, he was able to do that -- calling on Sanders to "accept some responsibility" for the virulent comments his supporters have made online and calling the Vermont senator a "socialist who thinks that capitalism is the root of all evil."

But the mayor's debate performance was also defined by attacks leveled against him from across the stage, primarily by Klobuchar -- who mockingly quipped she wished "everyone was as perfect as you, Pete."

Buttigieg's strategy of largely avoiding Bloomberg, who drew most of the fire on the debate stage, was clear. But just as apparent was how Buttigieg, despite leading the national delegate count after two states have voted, was searching for a moment that propels him forward as the Democratic race for president goes national.

"We've got to wake up as a party," Buttigieg said. "We could wake up two weeks from today, the day after Super Tuesday, and the only candidates left standing will be Bernie Sanders and Mike Bloomberg."

Klobuchar doesn't hide her contempt

Klobuchar speaks during a Democratic presidential primary debate

Klobuchar has turned in a series of strong debate performances throughout her presidential run -- usually happy-warrior performances with jokes sprinkled in. But Wednesday's was singular for another reason: The contempt she showed for Buttigieg and the frustration she has for Warren.

Klobuchar, at different points throughout the debate, turned to her left to take on Buttigieg with a fire that she hadn't previously shown on the debate stage. She accused the former mayor of calling her dumb and suggested that his entire candidacy was based on him memorizing "a bunch of talking points."

And when Warren hit Klobuchar for wanting to work with Senate Majority Leader Mitch McConnell, the Minnesota senator tersely said, "I am willing to work with people and find common ground and that's what we want in a president, Elizabeth."

There is no love lost between Buttigieg and Klobuchar -- a reality that was clear headed into the debate. And Klobuchar showed she believes Warren's style of leadership is divisive. But her fiery performance in Las Vegas was a divergence from the approach that had worked so well for her in New Hampshire -- and highlighted how desperately she needs a memorable moment to keep her campaign going as the pace of primaries ramps up.

The stage is set for a contentious convention

With such a crowded field, there is a real possibility that Democrats will go to their summer convention in Milwaukee with none of the candidates having clinched the nomination.

So, what then?

For five of the six candidates onstage, the answer was to roll the dice, perhaps allow superdelegates in on a second ballot and, as a couple put it, "let the process play out." Bloomberg, Warren, Biden, Buttigieg and Klobuchar all said that a candidate with a plurality of delegates should not automatically be handed the nomination.

Sanders, who could very well find himself in that position, was the lone voice of dissent. He said that the campaign with the most delegates, even if it fails to collect an outright majority, should win the nomination.

If what many Democrats consider a doomsday scenario occurs, and none of the hopefuls secure enough support to win the nomination on a first ballot, the contest could hinge on the preferences of nearly 800 superdelegates. And that, as anyone who remembers the controversy surrounding their impact in 2016 will recall, could be a recipe for an intra-party meltdown that would make the tough primary of four years ago look like tame.