"Huh? Yeah, yeah I am!" Papyrus says, stopping and swiveling in search of the voice's origin. The echoing of sound through narrow tunnels isn't a totally unfamiliar thing, but these are especially narrow and winding, adding to the difficulty of it... "Is someone else there?"

The person calling out, he means. It's likely they're in these tunnels as well, originating from a person near enough to hear... but not guaranteed! Some people are great at throwing their voices, after all. Some are great at faking voices, and maybe it's the unfriendly spider monster pulling an added trick. And there's always echo flowers.