New Super Mario Bros. U: Superstar Road-5 --Spinning Platforms of Doom

It's another Starry Night level. You can get the Acorn Mushroom here. The "spinning platforms of doom" are stones that rotate over the purple water, some of which are on paths. The first set of stones are in a group of four. Once you reach the end, swing on a vine and take the lower path by flying over the water. This will allow you to reach the first Star Coin, which is in a ring of Boos. The second Star Coin is nearby, in between two rotating stones on a path, in a ring of Boos. Drop down between the two stones and wall jump if necessary to get the Star Coin. Soon, you'll come to some land. In front of the blue pipe with the Piranha Plant is a brick block with a vine. Pound the brick block so that the vine goes into the purple water. Use the vine to reach the area under the pipe, where another blue pipe is hidden. There's a set of two stones in the water that don't rotate. Wall jump between the two stones as they move. Jump up in the alcove for the third Start Coin, then go back between the two stones until you reach the pipe. Next are a set of rotating stones that can be a little crazy. They will take you to the flagpole. This opens the path to a Mushroom House.