The Donald has had plenty of practice in his four decades in the spotlight, waging wars with celebrities like Rosie O'Donnell, Cher, Martha Stewart – and even President Barack Obama.
Let's take a look back at his most infamous feuds.
Trump Vs. O'DonnellTrump's tussle with O' Donnell dates back to 2006, when the then-co-owner of the Miss USA pageant decided not to fire crown-holder Tara Conner after revelations of drug use and underage drinking. O'Donnell, a cost-host on The View at the time, blasted Trump's decision and compared him to a "snake-oil salesman on Little House on the Prairie." She also said he went bankrupt and criticized his multiple marriages: "[He] left the first wife – had an affair. [He] had kids both times, but he's the moral compass for 20-year-olds in America. Donald, sit and spin, my friend."
Trump responded to the comments by telling PEOPLE O'Donnell was "a woman out of control" and a "real loser."
"You can't make false statements," Trump told PEOPLE at the time of O'Donnell's bankruptcy accusation. "Rosie will rue the words she said. I'll most likely sue her for making those false statements – and it'll be fun. Rosie's a loser. A real loser. I look forward to taking lots of money from my nice fat little Rosie."
In the years since, the two have traded biting barbs – and videos – on Twitter, though not without their own special brand of humor.
Fox News' Kelly reignited the feud, albeit unintentionally, at a Republican debate in August, where she grilled Trump about the derogatory words he's used to describe women. "You've called women you don't like fat pigs, dogs, slobs and disgusting animals," she began.
"Only Rosie O'Donnell," Trump interrupted.
Which prompted this tweet from O'Donnell: "try explaining that 2 ur kids."
Trump Vs. Spy MagazineOne of The Donald's oldest feuds is with Spy magazine, which in 1988 famously described the real estate mogul as a "short-fingered vulgarian." Trump continues to hold a grudge against the satirical magazine's co-founder Graydon Carter, now the editor of Vanity Fair, tweeting in November 2015: "I have watched sloppy Graydon Carter fail and close Spy Magazine and now am watching him fail at @VanityFair Magazine. He is a total loser!"
Trump Vs. StewartTrump sparred with Stewart over her short-lived version of The Apprentice, calling her performance "terrible." She fired back at Trump in a 2015 appearance on Watch What Happens Live, saying of his reality TV success, "It's fantastic for him … he's built a new platform ... so now he thinks he can be president."
Trump Vs. ObamaTrump made headlines in 2011 when he launched a "birther" movement against Obama, demanding the president release his birth certificate to prove that he was born in the United States. Trump stood by his attacks, even after Obama released a long-form version of his birth certificate.
The president got his revenge at the 2011 White House Correspondents' Dinner, where he mercilessly roasted an unamused Trump – who was sitting in the audience at the time.
"No one is happier – no one is prouder – to put this birth certificate matter to rest than The Donald," Obama said. "And that's because he can finally get back to focusing on the issues that matter: Like, did we fake the moon landing? What really happened in Roswell? And where are Biggie and Tupac?"
Trump Vs. CherCher dumped on Trump in 2012 after an online petition demanded Macy's sever ties with the billionaire businessman over his controversial birther views.
"I'll NEVER GO TO MACY'S AGAIN ! I didnt know they sold Donald Trump's Line! If they don't care that they sell products from a LOUDMOUTH … RACIST CRETIN,WHO'D LIE LIKE 'HIS RUG' TO GET SOME CHEAP PRESS ! I CANT BELIEVE MACY'S THINKS HE'S THE RIGHT 'MAN' 2 REPRESENT THEIR NAME !" she tweeted at the time.
Trump had some choice words for the singer in response: "@cher – I don't wear a 'rug' – it's mine. And I promise not to talk about your massive plastic surgeries that didn't work."
"@cher should spend more time focusing on her family and dying career!" he said in another tweet.
Later that year he threw more shade at Cher, tweeting, "@Cher attacked @MittRomney. She is an average talent who is out of touch with reality. Like @Rosie O'Donnell, a total loser!" – and proving that it always seems to come back to The Donald vs. O'Donnell.