There are two R.O.B. appearances in the Port Town Aero Dive stage. To see his first appearance, pause game play just after the platform passes the finish line and begins traveling down the series of ramps. There should be a large tower behind you. Rotate your view and look at the top of the tower. To see his second appearance, pause game play after the platform passes over the large black ship with the turbines on it then look to your right. Note: The second R.O.B. is much easier to see because it is huge.