Super Mario Galaxy takes traditional platforming and sets it deep in space in one of the best video games of all time. Left over in the game are traces of all the ideas that didn't quite make it into the game, from lost planets to unused enemies to early models. A few of these ideas were worked into the sequel.
StarManFort is a high-quality planet that was ultimately scrapped, much to the dismay of the development team. The two pipes on the planet are not warps but instead have the fully modeled tube interior, with the second pipe leading from the top of the tallest roof to the spherical underside of the planet. The yellow structure bears the same electric symbol as the ChargeSpot model. It, too, has concept art in the Prima guide. As can be seen by the concept art, it went through several incarnations, with the last two being left in the game's files. The version seen in the concept art depicts features such as a snowy area and a construction site.
It's also interesting to note that this same image also shows BossCrab, Planet Disk, and three copies of the Star Planet. It also shows some generic spherical planets and the spaceship planet used in Space Junk Galaxy.