In the while that he's been loitering in the tavern without drinking, he's startled a couple customers badly enough to swear or drop things just by sitting there.

Now it's his turn to startle, recognition a jolt through him. That map drops to the bar all but forgotten, settling to soak up a small uncleaned spill there, as Papyrus turns to stare with widened eyesockets.

"Wha-- Yeah! Have you seen him?!" His voice is frankly too loud for the room, for all it isn't quite a shout.

That greeter and mayor hadn't mentioned anything about meeting other skeletons, but, well... Sans could have wandered off in a shortcut as soon as the ferry docked, and never crossed their paths.