This week, the investigation into possible Trump-Russia collusion during the presidential election went up to 11—this following the Comey memo revelation that President Trump had, during a secret White House meeting in February, allegedly asked the then-FBI director to end the probe into his former national security adviser, Michael Flynn. Comey was fired a few months later.

The news prompted Deputy Attorney General Rod Rosenstein, who’s taken the reins on the Trump-Russia probe following AG Jeff Sessions’ recusal after lying under oath, to appoint former FBI director Robert Mueller as special counsel charged with overseeing the Trump-Russia inquiry.

And Stephen Colbert is delighted.

“The word ‘dumpster fire’ gets thrown around so casually these days, but when a special counsel gets appointed to investigate your administration just four months in, that’s a new high and low,” asserted Colbert during Thursday’s Late Show monologue.

Colbert, of course, is Donald Trump’s late-night enemy No. 1. After Colbert cracked an off-color joke about the president, the commander-in-chief retaliated by complaining to Time magazine that the comedian was “filthy” and a “no-talent guy.” Yes, Donald “grab them by the pussy” Trump just called Stephen Colbert, a Sunday school teacher, “filthy.”

So all of this added controversy is surely tickling the comic, who just last week declared victory in his war of words with the leader of the free world.

“Now, the ‘twist’ is that the counsel was appointed by Deputy Attorney General—and lesser Buscemi—Rod Rosenstein,” said Colbert. “Remember Rosenstein? Last week, when the administration was looking for someone to blame for the Comey firing, they tried to throw Rosenstein under the bus, forgetting that as deputy AG, he’s actually the bus driver. Next up, Indictment Avenue!”

As far as the special counsel goes, Colbert remarked, “Trump should have seen this coming, OK? This should be no surprise to him—especially because, after all, it’s just keeping one of his campaign promises from the debates.”

He then threw to a clip of candidate Trump from one of the presidential debates chastising his opponent, Hillary Clinton.

“If I win, I’m going to instruct my attorney general to get a special prosecutor to look into your situation,” Trump told Hillary.

“He’s a man of his word,” said a grinning Colbert.