What is this random hose hanging in my engine bay?

[fun173]

Hey everyone,

I opened up my hood to start cleaning the Manifold a bit then I saw a hose hanging randomly off the circular black tube next to the radiator. I have no idea what the heck this thing is. I have never seen it before. Any one know what it is or where it is supposed to be. It is attached to the bottom of the black circular thing. Check out the pictures to see what I'm talking about.

First Pic: This is what I saw when I opened the hood. It was just hanging down there

Second Pic: The yellow circle shows the top of the hose (I pulled it up to get a better look at it when I was it) The second yellow circle shows where the hose was connected to.

Let me know if you need any more pics.

The car is running fine except for my horrific idle.......