In what is now the natural order of things, Donald Trump made a mistake and J.K. Rowling tweeted about it.

On Thursday, President Donald Trump — currently in Brussels attending the NATO Summit — appeared to shove Montenegro's Prime Minister Dusko Markovic while making his way to the front of a small crowd. Later the White House reportedly defended the gesture as a "casual greeting" between leaders.

Did Trump just shove another NATO leader to be in the front of the group? pic.twitter.com/bL1r2auELd — Steve Kopack (@SteveKopack) May 25, 2017

Naturally, author J.K. Rowling — ever ready to offer her take on current affairs — read Trump's gesture as aggressive, and called him out for it on Twitter.

Rowling has long made vocal her issues with Trump, and regularly spars with his most fervent supporters online. The lesson: Don't cross Rowling via Twitter unless you're prepared for a highly public response. That is, unless you're Trump — she's coming for you either way.