strange hose
 

So I was reattaching all the carpet in my trunk, and I found this strange hose (perhaps 1/2 inch dia.) leading down past the factory amp in rear driver's side. I pulled the hose up, and its not attached to anything on the bottom, but I couldn't tell where it was coming from on the top end. Its not a place in the car where I would expect to find anything very important, but does anyone have any idea what that hose is for or where it leads?

its a water drain from the antenna area around the hatch opening. I don't know exactly where it starts but that is what it is.