Christie Endorses Trump, Rubio-Cruz Attack The Donald, Trump University Investigated

Marco Rubio now knows the fury of Donald Trump when he's scorned.

The Republican front-runner on Friday hit back at the Florida senator who rattled him in a CNN debate the night before by unveiling the bombshell endorsement of New Jersey Gov. Chris Christie on an extraordinary day when the already wild 2016 presidential campaign turned into a political bloodbath.

Christie showed up unannounced in Fort Worth, Texas, to laud Trump and savage Rubio, drawing gasps from reporters, after concluding the billionaire was destined to win the Republican nomination and was the best person to slug it out with Hillary Clinton for the White House.

"I will lend my support between now and November in any way for Donald," Christie told shocked reporters before Trump fired up a rally in the state with most delegates up for grabs in the Super Tuesday primaries next week.

Riding high off a strong debate performance, Marco Rubio went after Donald Trump on Friday with new vigor -- even mocking the real estate mogul for worrying that his pants were "wet" Thursday night at the CNN GOP debate.

The Florida senator spent the first roughly 10 minutes of his rally in Dallas, Texas, on Friday morning relentlessly attacking Trump, including reading off misspelled tweets and turning Trump's attacks back on the reality TV star.

"He called me Mr. Meltdown," Rubio said, smiling and saying that Thursday night during the commercial breaks, "he went backstage, he was having a meltdown."