New Super Mario Bros.: 5-C

It's another underground level. This time, the place has both Buzzy Beetles and Bruisers. Let the Bruisers break through the blocks for you. They can help you reach the first Star Coin encased in brick blocks. Past the first Star Coin are infinite platforms moving towards the ceiling or the void. Once past those, use a Buzzy Beetle shell to get the second Star Coin, floating over the void under the higher route. You'll soon find a Bruiser on some stairs. Clear away the top middle blocks near the ceiling. Hit the far right block in the row below to make a vine appear. It will take you to an area with a P-Switch and a Bruiser. Hit the switch, then lure the Bruiser to the left so it will destroy the blocks protecting the third Star Coin. From here, you can drop down to the goal. There's a ? Switch after the vine which makes red blocks appear over the void. Bruisers will periodically drop down and destroy the red blocks. Take it to the end, climbing quickly, as vertical walls will get in your way. At the end is a pipe to the flagpole.