Twitter swapped out its famous blue bird logo for an image of a dog long associated with cryptocurrency Dogecoin, which surged in value on Monday.
A small image of the Shiba Inu dog commonly known as Doge was seen at the top of the website's interface, replacing the standard Twitter logo.
“As promised,” Twitter owner Elon Musk tweeted, along with a screenshot of an exchange he had with a user who had suggested he “change the bird logo to a doge”.
Dogecoin surged by more than 16 per cent after the tweet.
The move comes days after Mr Musk asked a US judge to throw out a $258 billion racketeering lawsuit accusing him of running a pyramid scheme to support the cryptocurrency.
Lawyers for Mr Musk and his electric car company Tesla on Friday called the lawsuit by Dogecoin investors a “fanciful work of fiction” over Mr Musk's “innocuous and often silly tweets” about the cryptocurrency.
The lawyers said the investors never explained how Mr Musk intended to defraud anyone or what risks he concealed, and that his statements such as “Dogecoin Rulz” and “no highs, no lows, only Doge” were too vague to support a fraud claim.
“There is nothing unlawful about tweeting words of support for, or funny pictures about, a legitimate cryptocurrency that continues to hold a market cap of nearly $10 billion,” Mr Musk's lawyers said.
“This court should put a stop to plaintiffs' fantasy and dismiss the complaint.”
Investors accused Mr Musk, the world's second-richest person according to Forbes, of deliberately driving up Dogecoin's price more than 36,000 per cent over two years and then letting it crash.
They said this generated billions of dollars of profit at other Dogecoin investors' expense, even as Mr Musk knew the currency lacked intrinsic value.
The $258 billion damages figure is triple the estimated decline in Dogecoin's market value in the 13 months before the lawsuit was filed.
Dogecoin Foundation, a non-profit, is also a defendant and seeking the lawsuit's dismissal.
Reuters contributed to this report
