It was an apparent typo in a tweet by US President Donald Trump, and internet users have been mocking him mercilessly.
"Despite the constant negative press covfefe," he tweeted just after midnight, Washington time.
And he then appeared to have gone to bed, without finishing his thought or correcting his mistake.
Although it seems likely the word he was reaching for was "coverage", social media users have been trying to guess other alternatives or motivations.
Others deliberated on the pronunciation, and wondered why no aides had stepped in to alert him to the mistake.
Google Translate recognised the word as Samoan, though could offer no English translation.
(A BBC reader has written in to debunk any suggestion that the president is a secret Samoan speaker. Among many other reasons for this, the language does not even have a letter C.)
No time was wasted as some users put the word on a T-shirt, which they started to sell on eBay.
Someone also appears to have bought the domain name, covfefe.us.
Getting caught up in an explosion of memes, some social media users said they could not sleep, as everyone on the internet seemed to be trying to outdo each other with the best response.
And then Europe woke up, and it started all over again.
#Covfefe is currently a trending topic on Twitter across the world.
And when President Trump reappeared on Twitter, six hours later, he deleted the mistake, but seemed to be enjoying the spectacle.
He asked followers to keep guessing, while giving nothing away.