Wet-Dry World

Wet-Dry World is the eleventh course in Super Mario 64 (and its remake Super Mario 64 DS) filled with water. The water level of the course is controlled by the Seven Crystal Taps. The initial water level is altered at what altitude Mario Jumps into the painting to enter the level. Under Wet-Dry World is a "downtown" area. In Super Mario 64 the Underground City holds a Metal Cap, a Vanish Cap, and the eight Red Coins, while in Super Mario 64 DS the caps are replaced with Power Flowers.

The painting is in the second story of Peach's Castle and has a Skeeter on it. Various enemies inside include Amps, Skeeters,Heave Hos, and a lone Chuckya.

Levels
The level titles and numbers correspond to Super Mario 64 unless otherwise noted.

Star 1: Shocking Arrow Lifts!
From the start of this mission, the player should turn around right and run to the end of the long, wooden platform. After stepping on the floor switch, wooden platforms will appear. The player must jump across the platforms and go to the top of a large stone pedestal. There is a Crystal Tap on it, which the player must hit to raise the water level. Then the player should see several mini elevators, like the one in the Red Coin area in Hazy Maze Cave. They lead to a Yellow Box which contains the Power Star. Mario must punch the box to break it and get the star.

Star 2: Top O' the Town
In this mission, Mario must go up a narrow walkway. This will take Mario to the top of a large structure. A red and tan colored block is found nearby that Mario can push to get up to a higher area. Then he should walk across a long wooden plank and cross the platforms while avoiding enemies. After crossing everything afterwords, the star is found in the yellow ! box right up ahead.

Star 3: Secrets in the Shallows and Sky
In this mission, Mario must active five secrets by standing on or by manipulating certain objects. Once a secret is activated, a number will appear letting Mario know how many he has collected (much like when collecting red coins). The first secret is located by the far left wall. Mario needs to push the red trimmed block out of the way to the left (facing the wall) and a number will appear. The second one is within a yellow block to the right of the first secret. Opening the block actives the secret. The next one will appear up one level by the Heave Ho once Mario pushes the red trimmed block further into the wall. Another one is located up another level front the previous one and is on top of the grate with the star inside. The final one is near the fourth platform. The star appears near the start the level above a Star Marker.

Note: these can be collected in any order

Star 4: Express Elevator--Hurry Up!
The player will start this mission by diving into the water and swimming towards the nearby gray path. Instead of going up the path, Mario should swim under it to hit the Crystal Tap to lower the water level to its lowest point. Then Mario must make his way to the top of the tower. To get there, he needs to run around the corner of the tower until he reaches a Heave Ho mechanism running around that can toss him up to the second level, where a second Heave Ho is found that can throw him up to the highest level. Once there, Mario must turn right and go up to the cage with the star in the center. Mario should then step on the red floor switch to make the red-brick steps move and then climb them to the top of the cage. Just past the edge of the cage is a wooden platform that will act as an elevator. It will move up and Mario must then hop off the elevator and fall down to the floor below, outrunning the elevator. He then needs to quickly run into the cage at the bottom. Once inside the cage, he'll wait for the elevator to reach the bottom and jump on top of it. The cage will carry Mario to the top, but still inside the cage, allowing him to reach the golden power star.

Star 5: Go to Town for Red Coins
The red coins for this level are located in the Down Town section of the level. The two ways to get to it is to enter this level by jumping as high as possible in the painting, so the water level is at its peak and swimming to the grate in the corner of the level. Mario can also use the cannon in the level and blast to the entrance. Once Mario swims into the city, he must control the water and find the coins. There are a few on top of high buildings inside crates, so Mario will have to wall jump up walls to break the box and get them. The rest are in breakable crates around the city, along with one that seems to be on top of a church steeple. Once all the coins are found, the star will appear under the small house the is between the high walls.

Star 6: Quick Race Through Downtown!
For this mission, Mario needs to return to the Downtown section of the level and make the water level to it's lowest. There is a ! Switch located in the city behind a house. Activating it will temporarily create blocks inside the grate in the far corner. Mario will need a Vanish Cap to get inside the grate in the corner. The star is at the top, and Mario will need to reach it before the blocks disappear. An alternative to getting the star is to get through the fencing and Wall Jump up to reach the star.

In the DS version, only Luigi can get this star since he is the only character who has the ability to turn invisible.

Star 7 (DS): Soaked Silver Stars
The Player must swim at a certain water level and collect all five Silver Stars. The last one's in a crate where the player will need to lower the water level and punch to get. If the player's using Yoshi, they will have to use a Super Mushroom to break it, because Yoshi cannot punch blocks. The rest are found in the middle of the water and easy to get.

Downtown
To get to the abandoned downtown there are two ways. The player has to launch Mario into a very tall mesh cage with the level's cannon or jump into it when the water level is at maximum high tide (entering the level from the highest point of the painting). Once within the cage, the player must quickly swim through a tunnel with partially closed gates before Mario loses all of his air reserve.

The town has one Power Star and obtaining eight Red Coins can also unearth another Star. There are some enemies in Downtown as well, such as Skeeters and two Fire Spitters. The latter was removed in the DS remake because they were completely useless in the small amount of water found in Downtown. Other Items found here include green and blue ! Blocks. In the DS remake of the game, a lone Pink Bob-omb can be found, who reveals where the eight Red Coins are located.

Downtown is a somewhat modern yet small town, having only five buildings (which Mario cannot get into), plant life, and even a "central park" with thin stone walls and a statue of a pyramid. Another landmark is the small "shrine" that stands in front of the park. It has an opening where the player can collect the Star after gathering all eight Red Coins. It is unknown what the closed-off caged area was meant to be, if anything.

Trivia

 * This world was used in a Got Milk? commercial in the late 1990s, featuring Mario, who is unable to jump onto a platform in the first area, so he breaks through the screen, drinks some milk, becomes super-sized and starts walking on the top of the level.
 * Total coins in this course — 153.
 * Beta name on DS (as it seen in debug mode) "Water City".
 * One texture, used for the (unopenable) doors in downtown, was reused in The Legend of Zelda: Ocarina of Time.