Earlier this week, the national firefighters’ union endorsed Joe Biden for president, saying he was the candidate with the best chance of beating Donald Trump in 2020. As you can probably imagine, this didn’t go over so well with President Twitter, who’s known to fly off the handle at the smallest of perceived slights. But rather than simply shoot off a typical all-caps, unglued tweet or two before moving on, Trump had a massive, flaming meltdown that does not bode well for the next 552 days.

Lashing out at the union for having the audacity to throw its weight behind Biden—a move that apparently came as a shock to the White House, despite the president’s aggressively anti-worker policies, Trump wrote: “I’ve done more for Firefighters than this dues sucking union will ever do, and I get paid ZERO!” (He, Trump, is doing the work without expecting compensation, thank you very much.) He then proceeded to unleash a whopping five dozen re-tweets in the span of an hour, trashing Biden and the union and suggesting that firefighters actually have his back. Here’s a small representative sample:

Despite a history of flying off the handle via social media, Wednesday’s volume is a record for Trump, which might have something to do with the fact that he’s panicked about Biden‘s candidacy for office, and reportedly has no strategy in place to beat the former V.P. Earlier this month, before Biden even officially got into the race, Trump blew his top when Uncle Joe delivered a speech to the International Brotherhood of Electrical Workers and received applause and laughter from the crowd. “I’ve employed thousands of Electrical Workers,” the leader of the free world tweeted, like a lover scorned. “They will be voting for me!”

In addition to fear of a Biden vs. Trump general election, the president was presumably also on edge Wednesday morning thanks to the news that special counsel Robert Mueller wrote a letter to Attorney General William Barr criticizing the latter‘s characterization of the investigation into Russian election interference and whether Trump obstructed justice. Following his Biden tirade, the president tweeted:

Barr is expected to testify for most of the day on Wednesday, and potentially also on Thursday, so who knows what additional deranged ravings that will inspire. Stay tuned!

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