New Super Mario Bros. U: Layer-Cake Desert-2 -- Perilous Pokey Cave

As the name suggests, this level is filled with Pokeys. Use the pipe to go underground. There are pillars of sand that allow you to dodge some Pokeys, but some Pokeys may wander into them, making them difficult to avoid. Some Pokeys are on the ceiling. The first Star Coin is over a sand pillar near a Koopa. Between two Pokeys is a gap in the ceiling. There's an invisible block over the sand pillar between them. Use it to go up and over the ceiling for some coins and the second Star Coin. There's a Starman in the lower set of brick blocks. Past the midpoint is a set of blocks. Yoshi is in the top block. Go through the first pipe past the midpoint, which takes you to a dark cave. There is an invisible block between the two Pokeys on the ceiling, which lets you reach a green pipe overhead. It takes you to a lit cave with several tall Pokeys. Use Yoshi to bounce on top of the Pokeys for the third Star Coin. Once you return to the dark room, go through the pipe at the end. This will take you to the flagpole. The path to Fort opens.