This time, it’s over the numbers. Trump’s beef is that on her show, The Kelly File, the anchor cited a Fox News Iowa poll in which Sen. Ted Cruz (R-TX) had the lead over Trump. Not surprisingly, Trump would prefer that Kelly use a CNN poll—in which he had the lead. He took to Twitter to share his annoyance, though he never mentioned Kelly by name:

Why isn't anyone using the @CNN Iowa Poll with me having a big lead. They only want to use the one negative poll (2nd place).Dishonest press

— Donald J. Trump (@realDonaldTrump) December 15, 2015

However, in the same show, Kelly did point out that Trump has the lead in the national Monmouth University poll, though she misstated the numbers. The anchor said that Trump was “ahead of the pack by 15 points,” when in fact, the poll put Trump 27 points ahead of the runner-up Ted Cruz (41% vs. 14%). That was enough to prompt Trump to blast the anchor directly, calling her the “most overrated anchor” and “very bad at math”:

.@megynkelly, the most overrated anchor at @FoxNews, worked hard to explain away the new Monmouth poll 41 to 14 or 27 pt lead. She said 15!

— Donald J. Trump (@realDonaldTrump) December 15, 2015

.@megynkelly is very bad at math. She was totally unable to figure out the difference between me and Cruz in the new Monmouth Poll 41to14.

— Donald J. Trump (@realDonaldTrump) December 15, 2015

A Fox News spokesperson said the misstatement was due to an error in the script, and that Kelly would correct it during the CNN GOP debate on Tuesday night.

Never one to miss an opportunity to take shots at an opponent, the Donald continued to his Twitter tirade about Kelly “and her flunkies,” saying that he doesn’t expect to be treated fairly by Kelly in the aftermath of the debate. “Dopey Megyn Kelly lies!” he proclaimed.

I wonder if @megynkelly and her flunkies have written their scripts yet about my debate performance tonight. No matter how well I do – bad!

— Donald J. Trump (@realDonaldTrump) December 15, 2015

Between Iraq war monger @krauthammer, dummy @KarlRove, deadpan @GeorgezWill, highly overrated @megynkelly, among others, @FoxNews not fair!

— Donald J. Trump (@realDonaldTrump) December 15, 2015

I won every debate so far according to all debate polls including @DRUDGE_REPORT, @TIME @Slate and more. Too bad dopey @megynkelly lies!

— Donald J. Trump (@realDonaldTrump) December 15, 2015

As if she saw the Twitter onslaught coming, Kelly remarked on her show, “He does hold back in the debates, and then he gets on Twitter and…something else happens.”

Something else, indeed.

Note: This article has been updated to include a comment from Fox News.