“New drug coming out called Regretamine. Pop one & all regrets are gone,” the entrepreneur wrote in what appeared to be a simple joke – but the post has since taken on a life of its own, receiving tens of thousands of replies and retweets and almost 300,000 likes.
Some responded earnestly, expounding on the power of regrets and how “the best thing is to learn from such mistakes”.
But many more responded with their own jokes and online memes, including references to the cryptocurrency dogecoin.
Dogecoin started life itself as a straightforward joke posted online in 2013, but gripped imaginations and was eventually developed as an actual cryptocurrency.
In January and early February its value soared, shortly after Mr Musk tweeted that “Dogecoin is the people’s crypto”.
One user responded to Mr Musk’s latest tweet saying: “Anyone who sells dogecoin too early is going to need a boatload of Regretamine at some point in the future in order to stop regretting it.”
Another user shared a meme about the cryptocurrency, saying “Can’t see regretamine coming to the aid when #dogecoin rises massively cause folks didn’t believe in it.....it’s literally the currency of the future.”
Some wondered what impact Mr Musk’s tweet would have on the imaginary stock price of Regretamine.
While another user shared how glaring the irony would be if the pill had a side-effect on the digestive system.
Mr Musk himself rounded the circle by posting a dogecoin meme in response to his own tweet, a mispelled cartoon about a “Doge meme shield (legendary item)”. The follow-up tweet also received hundreds of thousands of likes.
Mr Musk’s devoted and sizeable following means his online jokes can often have serious real-world implications.
Last week it was reported that he was under investigation by US market regulators for his frequent posts about dogecoin – to which Mr Musk himself replied: “I hope they do! It would be awesome.”
Asked previously why he tweets so much about the cryptocurrency, Mr Musk replied: “I love dogs and memes.” And in a recent question-and-answer session on the app Clubhouse, Mr Musk said that his posts were “just meant to be jokes”, but added that “fate loves irony”.
He said: “The most entertaining outcome is often the most likely. Arguably the most entertaining outcome, and most ironic outcome, would be that dogecoin becomes the currency of Earth in the future.”