The tweet, which remains Assange's last entry as of 5pm GMT, includes a 60 character code composed of letters and digits, along with a link to M.I.A.'s Paper Planes, a song featuring the chorus "All I wanna do is (gunshot, gunshot, gunshot, gunshot) and (click, ka-ching) and take your money" and the lines "If you catch me at the border I got visas in my name" and "I've got more records than the KGB, So, uh, no funny business."
The message has led to a flurry of speculation over what exactly Assange was trying to say. Was it an encryption key indicating that a fresh batch of WikiLeaks files was on the way? Or a code for a 'dead man's switch' triggered to release its cache of 'life insurance' files in case the freedom of information activist was assassinated?
Other users voiced hopes that the post was an indication that the Trump administration had pardoned Assange. Others still said that the artist from the accompanying rap video was an important piece of the puzzle.
Others didn't attempt to guess the post's meaning, and turned to posting memes indicating their bewilderment, or simply wished Assange all the best.
The mysterious tweet follows the temporary deletion of the WikiLeaks founder's account on December 25, a curious occurrence immediately followed by the US Navy tweeting "Julian Assange" from its official Twitter account.
Assange has been living in the Ecuadorian Embassy in London since 2012, for fear of being extradited to Sweden on trumped up sexual assault charges. In 2015, the UN Working Group on Arbitrary Detention ruled that Assange's detention was arbitrary, but the UK and Swedish governments have refused to recognize the legitimacy of the UN's conclusions. Launched in 2006, WikiLeaks has released millions of classified documents related to espionage, war crimes, torture and other human rights violations. WikiLeaks' release of tens of thousands of files on Democratic presidential candidate Hillary Clinton is thought to have played a role in her defeat in the 2016 US presidential campaign.