Pivoting from the Montana special election to the Trump White House in his Late Show monologue Thursday night, Stephen Colbert said, “Meanwhile, remember the Russia scandal? That thing looms over Trump like a congressman over an unconscious reporter.”

The host went on to cite a recent story from The Daily Beast that reported the increasing anxiety of White House Chief of Staff Reince Priebus over the prospect that he could be ensnared in fired FBI Director James Comey’s detailed memos.

“We've learned that James Comey made detailed handwritten memos every time he spoke with the White House to ‘properly document conversations that were on the verge of improper,’” Colbert said, quoting the piece. “‘Verge of improper,’ of course, also the new series on Masterpiece Theater After Dark.”

The potential memo that has Priebus most worried, Colbert noted, is the one that likely followed a meeting in which he personally asked Comey to “knock down” any media reports about communications with Trump campaign staff and the Russians. “Yes, he wanted them to ‘knock down’ those Russian reports. And I’m being told we have a response from those Russia reports,” he said, before playing the chorus to Chumbawamba’s “Tubthumping.”

As The Daily Beast reported, one official described the feeling in the White House as “sustained panic,” which Colbert joked “also describes Sean Spicer’s daily press briefings.” Another official said the administration is “waiting for the other shoe to drop.”

“The other shoe? That's a lot of shoes,” Colbert said. “Well, I guess we'll find out all about it in Priebus' upcoming tell-all book, The Very Guilty Caterpillar.”