New Super Mario Bros. U: Peach's Castle-2 -- Magma-River Cruise

This level involves riding a raft in the lava. The raft has a number on it, and it drops by one for each enemy that is on the raft. Once the number drops to zero, the raft stops. There's a poisonous fog rolling in, which encourages you to keep the raft moving and clear of enemies. To help with the enemies, you can get an Ice Flower, which can help clear the raft like a shell. There are Monty Moles that will pop out of the scenery and drop down on the raft. The first Star Coin is high over the lava. Stand on the double brick blocks with the Koopa on the left wall, then jump up for an invisible block. Stand on the block and the double brick blocks will move into place so that you can reach the first Star Coin. Next are some Microgoombas, which will affect the raft, and some Blaargs. If you can hit the high, lone brick block, you'll get a 1-up. The second Star Coin is nearby, in some bricks. You can easily reach it by hitting the P-Switch. You can reach the second Star Coin from the raft, or from above. The third Star Coin is under the red pipe at the end. Wait for the raft to float under it to get it or use a shell. Once through the pipe, jump over the lava to reach the flagpole. This opens the path to Peach's Castle-3.