Michael Moore issues cryptic threat against Roseanne Barr and Donald Trump

On Wednesday, documentary filmmaker Michael Moore posted a mysterious threat on Facebook.

"I know Roseanne. And I know Trump. And they are about to rue the day they ever knew me," he wrote.

It's not clear what he's referring to, but  seems to tease a future project exposing Donald Trump and Roseanne Barr.

Moore, famously, is one of the few progressive voices that predicted a Trump victory in 2016.