In Brawl, R.O.B. never did have his own stage like the other characters. I decided to change this for Max. Later, it was redesigned and placed in X2.
The stage has a similar appearance to the other NES stages. There are tubes on the side that are a sort of mix of yellow and orange in color, one on the left side of the screen and two on the right side of the screen. If you enter one of the tubes on the right, you'll come out through the tube on the left. If you enter the tube on the left, you come out of one of the right-side tubes(the tube in question is chosen at random).
Those thin blue lines are elevators. Stand at the bottom of one and it'll carry you up to the next platform. There are red and blue tubes embedded in platforms that raise and lower at random. When they do this, they will close up some areas of the stage while opening up others. If they rise underneath you, you'll be pushed towards the ceiling. They don't move fast enough to crush you. If get caught between a tube and a platform, you'll be squished, but you won't die. In fact, you won't even take damage. It'll be hard to move out of there though.