Donald Trump jetted into Washington Thursday for his first official meeting with President Barack Obama, as the two men begin the process of transferring the powers of the Oval Office.
Although Obama struck a statesman-like tone in a national address Wednesday, saying Americans are all "rooting" for the success of the president-elect — a real estate developer taking on his first job in government — the two frequently traded barbs on the campaign trail.
We are all the White House staff watching Obama welcome Trump as next president. pic.twitter.com/cxB54V9x1S
— Emma Kennedy (@Nufanglenesse) November 10, 2016
Here's a look at some of their zingers:
In 2011, when Trump was not yet a candidate for the White House, he emerged as a driving force behind the fueled so-called "birther" movement that questioned whether Obama was born on US soil and thus eligible to be president.
An exasperated Obama was forced to produce his birth certificate to dispel the conspiracy theory.
A few days later, at the White House Correspondents Dinner, Obama skewered the billionaire — a public dressing-down that some observers suggested spurred Trump to run for high office.
"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?"
Obama = disaster
When Obama described the prospect of a Trump presidency as "scary," the freshly minted Republican presidential nominee struck back.
"I think President Obama has been the most ignorant president in our history. His views of the world as he says don't jibe and the world is a mess," Trump told reporters in July.
"He has been a disaster as a president. He will go down as one of the worst presidents in the history of our country."
'Unfit to serve'
Obama issued a searing rebuke as Trump stumbled through one of the roughest patches of his campaign in August, reeling from self-inflicted wounds after he criticized Muslims, firefighters and the military.
He called the 70-year-old mogul "woefully unprepared."
"The Republican nominee is unfit to serve as president," Obama said. "He keeps on proving it."
One of Trump's most outrageous outbursts at Obama also came in August when he said repeatedly at a rally in Florida that the president founded the Islamic State extremist group.
"He's the founder of ISIS. He's the founder of ISIS. He's the founder. He founded ISIS." He added, "I would say the co-founder would be crooked Hillary Clinton."
The next day, Trump doubled down when a reporter asked if what he meant was that Obama created a vacuum in the Middle East allowing the group to thrive.
"No, I meant he's the founder of ISIS," Trump said. "I do. He was the most valuable player. I give him the most valuable player award. I give her, too, by the way, Hillary Clinton."
As Trump pressed a conspiracy theory that the US election was "rigged," Obama abandoned diplomatic decorum and skewered the Republican in front of the visiting Italian prime minister in October.
"You start whining before the game's even over? If, whenever things are going badly for you... you start blaming somebody else, then you don't have what it takes to be in this job," Obama said.
"I'd advise Mr. Trump to stop whining and go make his case to get votes."
Finger on the button
Known for his unfiltered tweets, Trump was uncharacteristically restrained on social media in the final countdown to Election Day.
"Over the weekend, his campaign took away his Twitter account," Obama told a rally for his fellow Democrat Clinton.
"Now, if your closest advisers don't trust you to tweet then how can we trust him with the nuclear codes?"