Ty! It's the wall along the queue in Test Track. I can't remember the details of what kind of polymer it is, but it's some component in test crashes. I just love the color/texture.
Very cool! I've heard about the key but never knew where to look for it, I assumed it was somewhere in the preshow area. Oh how I wish I had a trip scheduled so I could look for all these cool new details that I've never seen!!