"He is deeply offended that I called him a metaphorical bedbug," Prof Karpf wrote in a tweet that has been shared nearly 12,000 times.
The internet quickly piled onto the former Wall Street Journal columnist, who attracts ire both from the Times' left-leaning audience for his columns about free speech and "cancel culture" and from right-wing critics of the paper for his anti-Trump stance.
Internet users flooded Stephens' Twitter with memes and pictures of bedbugs, and someone even briefly edited his Wikipedia page to describe him as "an American journalist, editor, bedbug, and columnist".
"Bret Stephens, a guy who professionally laments 'PC culture' and 'safe spaces' is upset someone jokingly called him a bedbug on Twitter," journalist Jordan Uhl wrote.
Democratic congresswoman Alexandria Ocasio-Cortez wrote, "Imagine being on Twitter and having the worst thing you're called in a given day is 'bedbug'. My own friends roast me harder than that."
She added, "For real though, it is pretty concerning that this guy abused his position to try to get someone fired over something so insignificant — especially after creating a career defending vile language as a sacred freedom and deriding people organising for basic human dignity as 'snowflakes'."
Fox News host Laura Ingraham also weighed in, writing, "Dish it out but can't take it department: Bret Stephens was upset that some professor called him a 'bedbug' on Twitter, so he sent him a personal note to complain (and a dinner invite) and cc'd his Provost."
On Tuesday morning, Stephens announced he was deactivating his Twitter account. "Time to do what I long ago promised to do," he wrote. "Twitter is a sewer. It brings out the worst in humanity. I sincerely apologise for any part I've played in making it worse, and to anyone I've ever hurt."
Appearing on MSNBC later that morning, Stephens defended his decision to copy in Karpf's employer. "I had no intention whatsoever to get him in any kind of professional trouble … but managers should be aware of the way in which their professors interact with the rest of the world," he said.
"Using dehumanising rhetoric like bedbugs or analogising people to insects is always wrong. There is a bad history of being analogised to insects that goes back to a lot of totalitarian regimes in the past."
In a statement posted to Twitter and addressed to Stephens, George Washington University provost Forrest Maltzman said Prof Karpf "speaks for himself and does not take direction from me". "His opinions are his own," he wrote. "Our commitment to academic freedom and free speech are integral to GW's mission."
"Bedbuggate" finally came to a head late on Tuesday night, with the US President tweeting, "A made up Radical Left Story about Doral bedbugs, but Bret Stephens is loaded up with them! Been calling me wrong for years, along with the few remaining Never Trumpers — All Losers!"
