Stubborn Shower Pipe! Tips?

[justinperkins]

I'm trying to replace my shower head, but to do so I have to remove the stubby pipe that comes out of the wall that you mount your shower head on. You know the one I'm talking about?

Well I can't get that darn thing off for the life of me. I've tried vise grips and channel locks but that sucker is really on there.

How can I get better grip on that slippery little pipe (it's chrome and perfectly round)??

What's the tool I'm looking for?