New Super Mario Bros./World 3-B

After the perils of World 3-2, you must face another sky-high challenge. Traverse across a passage formed entirely out of pipes; horizontal, vertical, tiny or warp-able. There isn't as much danger of falling compared to other athletic courses, but there are plenty of pipe-dwelling Piranha Plants, as well as their fire-breathing cousins. If you can clear this level, you will extend a major shortcut south of the other stages!

Level walkthrough
The stage immediately gives you an idea of what to expect the moment you enter it: lots of pipes, and annoying Piranha Plants that come out of them. Cross the first two vertical pipes, which happen to contain Piranha Plants, and hop to the four short pipes, where the block with the power-up is located. After that is a pipe containing the first of several Venus Fire Traps, followed by some normal Piranha Plants facing downward, then by another Venus Fire Trap. The block used to jump on to its pipe contains a power-up in case you're hit by any plants.

After the Venus Fire Trap is a brief moment of peace. There are no carnivorous plants to worry about as you collect coins above some pipe platforms. You can catch a glance of a Star Coin as you do, but there is no way to reach it currently. Past the yellow pipe platform, the density of Piranha Plants will start to increase, as there are some more of them packed closely around the chaotic arrangement of pipes. There is also another Venus Fire Trap, followed by a lone red pipe. Go down this pipe and head left, dodging any Piranha Plants in your way. There is a roulette block at the left side of this area, and if you go up the red pipe here, you can get to the Star Coin from before. Backtrack to the previous red pipe to return to the main stage.

Continuing forward, the pipes you can stand on get more spaced out, increasing the likelihood of you falling in. There are also more Piranha Plants lurking within them, and a Venus Fire Trap whose fireballs make jumping to each pipe a challenge of dexterity. After the Venus Fire Trap is a very long yellow pipe, the start of which contains the checkpoint flag. From the green pipe directly to the right of where the Venus Fire Trap is, jump up to the red pipe and wall jump over it to reach the an otherwise inaccessible tiny pipe platform with the second Star Coin.

Drop down and keep going right. The frequency of Piranha Plants will intensify even more, as you must now contend with branching pipes, each with these murderous plants in them. Two of these pipes also contain Venus Fire Traps. Despite their sheer number, you can still avoid getting hit by any plants by observing their patterns and timing your jumps right. As you near the end, you can see the last Star Coin. There are multiple ways to approach this coin, but the easiest is to go above it, passing the Venus Fire Trap, then move left as you fall down to get to it. To the right is a double-ended pipe containing two Piranha Plants. You can use it to jump to the top of the flagpole.

Star Coins

 * 1) When you first see this coin, it is inaccessible. Go down the first red warp pipe after seeing the coin, then go to the left of the secret area and take the red pipe up to collect it.
 * 2) From the pipe to the left of the middle checkpoint, wall jump up the gap between the two pipes to reach an area supported by a tiny pipe where the coin can be found.
 * 3) Out in the open near the flagpole. The only obstacle here are some dangerously-placed Piranha Plants.