Eccentric Twitter owner Elon Musk has sparked two separate controversies wth a single, two-word tweet.

Over the weekend, the Tesla founder decided to take on outgoing National Institute of Allergy and Infectious Diseases director Dr Anthony Fauci, tweeting out of nowhere that: “My pronouns are Prosecute/Fauci”.

He followed it up with a second tweet featuring a meme of Dr Fauci and President Biden with the caption: “Just one more lockdown, my king”.

Dr Fauci, who emerged as the face of the US’ Covid response and served as President Joe Biden’s chief medical adviser since January 2021, is America’s leading infectious diseases expert, and before the 2022 midterm elections, Republicans vowed to investigate his role in the pandemic if they won control of the House or Senate.

However, while Musk’s tweet attracted support from countless followers, as well as far-right congresswoman Marjorie Taylor Greene, who has recently been welcomed back to Twitter after being barred over Covid misinformation, it also prompted a barrage of backlash.

 “It’s America. You can select any pronouns you damn well please. But Anthony Fauci has likely saved more human lives than any living person in the world. Shame on you,” congressman Dean Phillips tweeted in response to Musk’s Dr Fauci dig.

“Re Musk tweet? Courting vaccine-deniers doesn’t seem like a smart business strategy, but the issue is this: could you just leave a good man alone in your seemingly endless quest for attention?” Senator Amy Klobuchar tweeted.

 “Dr Fauci is a national hero who will be remembered for generations to come for his innate goodness & many contributions to public health. Despite your business success, you will be remembered most for fuelling public hate & divisions. You may have money, but you have no class,” former CIA director John Brennan also tweeted.

In addition to the debate over America’s Covid response, Musk’s tweet also kicked off arguments surrounding the issue of the use of pronouns and gender identity.

Musk, who has a transgender daughter, caused a stir back in 2020 when he tweeted “pronouns suck”, before being publicly scolded by then-partner Grimes, who responded: “I love you but please turn off ur phone or give me a (call). I cannot support hate. Please stop this. I know this isn’t your heart”.

• ‘Report at 2pm’: Elon Musk fires off stern new email to Twitter staff
• Elon Musk sacks Twitter developer after public spat over slow app performance
• Mass exodus chaos: Twitter locks buildings, workers set to quit after Musk ultimatum

Musk’s latest controversy comes after an explosive analysis by Media Matters revealed late last month that 50 of the top 100 advertisers had either announced or seemingly stopped advertising on Twitter.

These advertisers have accounted for nearly $US2 billion ($A2.9 billion) in spending on the platform since 2020, and over $US750 million ($A1.1 billion) in advertising in 2022 alone.

In addition to advertisers that have seemingly stopped all advertising on Twitter as of November 21, there are an additional seven advertisers which appear to be slowing the rate of their advertising on the platform to almost zero.

Since 2020, these seven advertisers have accounted for over $US255 million ($A331 million) in spending on Twitter, and nearly $US118 million ($A173 million) in advertising in 2022.

But despite the painful advertiser exodus, Musk has doubled down on divisive behaviour such as amplifying conspiracy theories, reinstating banned accounts including former US President Donald Trump and engaging with far-right users.

In recent weeks, Musk has also been under fire after it emerged officials are investigating reports he converted offices in Twitter’s San Francisco headquarters into bedrooms for tired staffers amid his new “hardcore” work culture.

BBC North America tech reporter James Clayton obtained and shared multiple images of rooms within Twitter HQ that have been converted into bedrooms. He said the publication was also told that Musk regularly sleeps at the building.

According to the photos, sofas had been turned into makeshift beds with some rooms boasting wardrobes and even slippers, which sparked safety concerns and backlash against Twitter’s purported brutal work culture.