New Super Luigi U: Meringue Clouds-6 -- Three-Headed Snake Block

As the title suggests, the snake block in this level will split into three early on. This is an automatic sidescroller. Beware of the Foos and the fog they create. You can spin to clear it up. Stay on the bottom snake block for the first Star Coin. Get an Acorn and you'll find the second Star Coin hidden in a cloud near the top past the Red Coins. The third Star Coin is nearby, towards the top. The snake blocks will take you to the flag.

New Super Mario Bros. U: Meringue Clouds-6 -- Snaking Above Mist Valley

This is an automatically sidescrolling level with few enemies. Activate the snake block to get going and you'll pass some Foos, clouds that produce fog. You can spin to clear it or kill them with a stomp or a shell. You can get the Acorn Mushroom here. The first Star Coin is under a piece of land on your path with a P-Switch. You can either go under the piece of land with the snake block or go up and over the land, then double back to the left. The snake blocks will move straight up so you can get the second Star Coin. After a while, you'll arrive at a pipe, which takes you to the midpoint. There's another snake block, with a Fire Bro nearby. Near the next piece of land is a Green Ring. The third Star Coin is floating over the void past some Parakoopas. Use a shell before the snake block blocks you to get it. At the end is a pipe to the flagpole. This opens the path to the castle and a Mushroom House.

New Super Mario Bros. Wii 7-5 QSC

In the area past the midgate with 3 Foos standing on parts of rock, a Paragoomba with Microgoombas, and a red Koopa, I got the 3rd Star Coin. I just walked through the rock wall where the first Foo was and found the Star Coin there.

New Super Mario Bros. Wii: 7-5 -- High Chance of Fog

This level brings back the annoying Micro Goombas, which make jumping difficult. Also appearing are fog-making clouds called Foos. I got the first Star Coin and killed some Foos by stomping. I reached the midgate. I used a Helishroom to get the 2nd Star Coin, but lose the Helishroom to a Paragoomba. I lost the Super Shroom to a Koopa and reached the goal.

After the Game Over:
Take 1- I got a Fire Flower and killed some Foos and got the 1st Star Coin. I reached the midgate. I used a P-switch to get the 2nd Star Coin. I lost the Fire Flower to a Koopa, the Super Shroom to a Paragoomba, but got a 1-up at the goal.