Colorful Coral Caverns if the 6th main level of Super Mario Star Road. Once you obtain the key from Bowser's Slippery Swamp, you can enter the main castle. Once inside make your way up the stairs and take the star door on the right, which will lead to a warp pipe. This warps you to the submerged sewers of the castle (Flowpipe Sewers), where the next few stages are located. The one in question in located in a bigger green pipe across for floating wooden planks near the entrance. It is also worth noting that a lot of this stage can be clipped through to gain shortcuts.