In his opening monologue Tuesday night, "Hannity" host Sean Hannity blasted former three-term New York City mayor and billionaire Michael Bloomberg for his insanely expensive marketing campaign and his left-wing ties.

As 2020 Democrats are poised to take the debate stage in Nevada Wednesday evening, Hannity said Bloomberg didn't win his spot fair and square.

BLOOMBERG HITS BACK AFTER TRUMP SAYS 'MINI MIKE' IS 'ILLEGALLY BUYING THE DEMOCRAT NOMINATION'

Bloomberg, the wealthiest candidate in the race, despite competition from billionaire Tom Steyer, has picked up steam in recent weeks after aggressively pouring more than $300 million of his own money into TV advertising alone to drum up support in Super Tuesday states.

He is reportedly worth $53.4 billion as of 2019, according to The Forbes 400

Bloomberg's upcoming debate debut drew criticism from detractors who accused the Democratic National Committee of relaxing one of their criteria, which calls for a candidate to have a certain number of donors to qualify for the debate, in order to include Bloomberg.

However, without former Vice President Joe Biden and Democratic socialist Sen. Bernie Sanders, I-Vt., as viable options for the liberal party leadership to push forward into the nomination, Hannity said Democrats are onto "Plan B."

"That would be billionaire farmer Mike Bloomberg who just scored a spot on the debate stage but – oh, let's see – only had to spend a slick $417 million to date in marketing campaign with zero vetting until this week and that is just the tip of the iceberg," he said.

"The past three years Bloomberg has shelled out tens and tens of millions of dollars to Democratic campaigns and...left-wing causes all around the country including this...anti-Second Amendment activism of his and radical environmental views," he continued.

"Now Bloomberg is calling to collect in the form of endorsements," he explained.

Bloomberg has said he is willing to spend upwards of $1 billion on his campaign, an unprecedented amount of money by any presidential campaign in American history.

Hannity said that the president hit Bloomberg's campaign issues on the nose in a series of tweets Tuesday night.

"What Mini Mike is doing is nothing less than a large scale illegal campaign contribution. He is “spreading” money all over the place, only to have recipients of his cash payments, many former opponents, happily joining or supporting his campaign. Isn’t that called a payoff?" he wrote. "Mini is illegally buying the Democrat Nomination. They are taking it away from Bernie again. Mini Mike, Major Party Nominations are not for sale! Good luck in the debate tomorrow night and remember, no standing on boxes!"

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"Why do you want to run against Bernie so badly?" Bloomberg later quipped at Trump.

"Mini Mike. No, I would rather run against you!" the president replied.

According to the most recent Real Clear Politics matchups, polling indicated that Bloomberg would beat Trump in a November faceoff by 5.7 percentage points, 49.5 to 43.8.

It also predicted Sanders would beat Trump by 4.1 percentage points, 49.1 to 45.

Fox News' Vandanda Rambaran and The Associated Press contributed to this report.