New Super Mario Bros. U: Acorn Plains- Castle -- Lemmy's Swingback Castle

As the name suggests, there are lots of swings in this castle. There's also lots of lava. Get the Acorn Mushroom, then the first Star Coin by transferring swings. Avoid the Podoboos and use the tiered swing to reach the higher swing to the right. When you reach solid footing, you'll find the midpoint nearby. The floor will end and you'll have to deal with more lava. Use the Acorn Mushroom to glide for the second Star Coin. Afterwards is a Red Coin Ring. The swings will be much closer to the lava and some will go into the lava, so jump when they do. There will be more swings, then a pipe in the lava. Carefully drop down to it. It leads to another room with lava with a swing that goes into the lava. The third Star Coin is above the swing, so get on the swing, then jump to get the Star Coin when it goes into the lava, then land when the swing is out of the lava. Return to the main level. You'll be near the boss door. There's a Fire Flower in an invisible block on the right wall. The door leads to an open part of the castle where we can see Lemmy's Airship flying by. At the top of the stairs is a cannon, which will blast you to the Airship. We land inside the Airship where Lemmy is. Lemmy stands on a bouncy ball and throws bombs. Avoid the bombs and stomp Lemmy. He'll go spinning around in his shell, then stop, and stand on another bouncy ball and start throwing bombs again. The best way to deal with the Koopalings is to stomp them as soon as they get out their shell cycle. Three stomps are all you need to defeat him. We win and Mario stomps around on Lemmy's Airship, which flies off and crashes somewhere. We save the game and head to the next area, Layer Cake Desert.