The paper salesman cometh.

It’s Always Sunny in Philadelphia star and creator Rob McElhenney posted a video to Instagram on Thursday from what appears to be the exterior set of another beloved Pennsylvania-based television show — The Office.

The video suggesting a possible crossover sent fans of both shows into a bigger frenzy than Meredith after she was bitten by the rabid bat that Dwight trapped to her head with a garbage bag. Or Michael Scott during a fire drill.

Like Charlie unraveling a vast conspiracy on his wall, fans have already started to outline detailed plot points they’d like to see in an It’s Always Sunny-Office mashup.

In McElhenney’s short video, he said he was outside what was once the exterior of Dunder Mifflin, the fictitious Scranton paper company where The Office was set.

“They’re gone now. They’re off the air and now you got — sorry Carell — these guys now," McElhenney says before panning the camera to Charlie Day and a pantsless Danny DeVito.

“Ehhhh!” DeVito responds.

And Toby thought Michael Scott was an HR nightmare.

“I guess your show got canceled or whatever but we’re still doing ours so we’re doing it here,” McElhenney taunts Carrell.

On Instagram and Twitter he captioned his post: “The bar inside Dunder Mifflin is now called Paddy’s."

Office star Steve Carell responded on Twitter on Friday: “Rob, this blood feud has to end. ‘It’s Always Sunny in Scranton’. Thoughts?”

We can already see it now: Danny DeVito and Meredith wasted on a date neither will remember; both casts racing in the Dunder Paddy Philly Scranton Sweet Dee Memorial Instafamous Rabies Sun Run Dash for The Cure for Hangovers; and kitten mittens trapped in Jello molds.

On Friday, McElhenney upped the ante by offering not just an episode — but an entire series crossover .... for $500 million.

While set in Pennsylvania, both shows have filmed mostly in California.

But the cast of The Office is no stranger to Pa. In 2007 and again when the show went off the air in 2013, cast members traveled to Scranton for “Office parties” held by the town.

Given that rumors of a reboot of The Office have swirled for years and that fans are upset by this week’s news that the show will stop streaming on Netflix in 2021, it could be a perfect time for the cast of The Office to show up on It’s Always Sunny.

Only then, perhaps, could the gang solve the paper crisis.