World 6-3 (New Super Mario Bros. 2)

World 6-3 is the third main level in World 6 of New Super Mario Bros. 2. This level contains many stretching mushrooms which live underground. Gold Rings also appear in this level, along with enemies like Fire Bros. and Koopa Troopas.

Layout
At the start of the level, the player must go down a red pipe leading underground. There is also a 1-Up Mushroom that can be seen at the far side before going underground. Once underground, the player encounters many stretching mushrooms, a few Koopa Troopas, and two Fire Bros. throughout the section. Before the Checkpoint Flag, there's another stretching mushroom that leads to the first Star Coin, which the player must duck to collect. After the Checkpoint Flag, there is a Red Ring with four stretching mushrooms where the player can collect an item. After this, there's a straight path with more stretching mushrooms, after which is a yellow pipe that leads to the second Star Coin, Fire Bros., and a Gold Ring. If the player continues forward and goes to the far end when they pass through more Fire Bros. and a Gold Ring, the third Star Coin can be collected by going on the top platform with a red pipe that leads to the exit. If the player goes across the bottom, there are a few more stretching mushrooms with lots of Coins until they reach the yellow pipe. This pipe also leads to the exit. The Goal Pole then appears with a Koopa Troopa along the steps. The player can only get to the top with Raccoon Mario.

Star Coins

 * Star Coin 1: This coin is on top of an extending magenta mushroom platform, but is covered in Brick Blocks. The player must use the nearby Red Koopa Troopa shell to get rid of the bricks that block that Star Coin.
 * Star Coin 2: When the player sees the third Fire Bro., they must enter the yellow pipe to take them to a secret room with two Fire Bros. and the Star Coin.
 * Star Coin 3: Before the exit, the player must run on the Brick Block ceiling instead of the lower magenta mushroom platforms to find a hidden path to the third Star Coin. This concept was already used in other games, such as in World 1-2 of New Super Mario Bros, or even in World 1-2 in Super Mario Bros and Super Mario Bros: The Lost Levels.

Enemies

 * Koopa Troopas
 * Fire Bros.