New Super Mario Bros./World 6-3

A mountainous rainforest is cooler and less humid, but its still home to plenty of Piranha Plants and the occasional Venus Fire Trap. Like in the jungle of World 4, there are wide streams of deadly poison water, but the lethal river flows underground here. With the amount of warp pipes jutting out of the ground, it can be quite difficult to keep track of your location.

Level walkthrough
At the start, you can see a red question block in front of you. They have a spike on one of their sides and rotate regularly. The spikes are obviously dangerous, but you can render it harmless by hitting it from a non-spiked side, upon which it will drop a power-up. Jump over the hill and two Piranha Plant infested pipes to see the first Star Coin. There is a block attached to a string which wildly swings around in odd directions. You must get on to the block and jump from it to reach the Star Coin. If that's too hard to accomplish, you can attempt to hit the block, which causes it to stop swinging and hang loosely, and you can still jump to the Star Coin in this state.

Jump over the gap and go down the red warp pipe to be taken to an underground cave. Poison water, the main hazard from World 4, returns, and it is just as lethal as before. There are huge logs that act as platforms over the water, but they roll when you stand on them, causing you to slide down slowly. Keep moving and jumping to minimize your chances of falling in. There is a red ring here which spawns red coins along the surface of the logs, which can let you get an easy power-up or 1-Up. Go through the red pipe at the end to return to the surface.

You end up standing on the first of a series of pipes, many of which contain Piranha Plants, and some Venus Fire Traps. The warp pipe adjacent to you takes you to a small chamber with some coins, as well as a Star Coin visible but inaccessible. Go down the pipe immediately to the right of the previous one to enter the cave with the Star Coin. Finally, go down the rightmost pipe to progress. You will end up in another underground poison lake, which also have logs used to cross it. There are many pipes with Piranha Plants here, so you must be more cautious when running across the logs. The pipe at the end takes you to the surface again, right next to the checkpoint.

Back above ground, you can spot another rotating red question block. Hit it to deactivate it, then jump on the block. Now, make a running leap toward the left pipe wall. You should jump high enough to leap over the pipe, landing in an otherwise blocked-off area with the third Star Coin. To get out, wall jump between the two pipes. It is possible to jump over the left pipe was well, but this forces you to replay a previous section of the level, so try to avoid doing so.

Continuing forward, you will encounter a Moneybag, a very rare enemy. Follow it to the right, carefully leaping over the small gaps in between narrow columns. Corner it against the pipe and kill it to get a bunch of coins. Use the blocks in front of you to ascend to the pipe to the right, then make a leap to the flagpole to complete the course.

Star Coins

 * 1) Get on the first erratically bouncing block and jump to the Star Coin in the air to reach it. You can hit the block first to stop its movement, letting you get on it easier.
 * 2) After exiting the first poison lake area, go down the third pipe from the left to drop into a cave with the Star Coin.
 * 3) Once you emerge from the second poison lake section, hit the rotating block to stop it from spinning. Do a running jump from the block to the left to get over the green pipe and fall to the small area with the Star Coin. Wall jump to exit.