Vent pipe -- what's that?

And why is this guy smiling, you ask? Perhaps a suspiciously damp odor required the impromptu removal of some basement drywall, revealing the worst framing job he had ever seen. In his whole entire life. Or maybe it was the discovery of a vent pipe TO NOWHERE. Until we can get a plumber out here we have a designated monitor when emptying the kitchen drain. But we haven't stopped smiling.