The Elon Musk/Twitter drama continues. In a surprising announcement, Musk has revealed his deal to buy Twitter for $44 billion is now on hold. The news has sent Twitter shares plummeting in pre-market trading. TWTR is down over 18% as of the time of this writing.

The latest twist in the saga broke when Musk tweeted, “Twitter deal temporarily on hold pending details supporting calculation that spam/fake accounts do indeed represent less than 5% of users.” The tweet linked to a May 2 Reuters article, which reported that Twitter estimated fewer than 5% of its monetizable daily active users (MDAUs) during the most recent quarter were fake or spam accounts.

Musk’s planned acquisition of Twitter is perhaps the most contentious in tech history. The Tesla CEO has frequently said he is a free speech absolutist and would allow currently banned users like former President Donald Trump back on the platform, leading to fears that Twitter could become a place where abuse and fake news is even more prevalent than it is today.

Today’s announcement by Musk now shows the deal is anything but certain. However, backing out of said deal could cost the world’s richest man. Twitter and Musk have agreed to pay the other $1 billion should either side pull out.

Shares of Tesla were up almost 6% in pre-market trading.