Skyhigh Pipelands

Skyhigh Pipelands is an anomalous sky-themed level with several pipes of varying sizes that was first documented by Youtuber BlackJoystick. The level has been reported to appear from the Painting Creator anomaly, though has been reported to be accessed through a pipe or painting found somewhere in Princess Peach's Castle.

Geography
Skyhigh Pipelands takes the appearance of a large, cloudy area with several large pipes throughout the level. Most pipes usually allow the player to jump on them, though some have been reported to have a gust of air that pushes the player up or a bottomless pit. Some pipes have also been reported to emit water. Notably, one report of Skyhigh Pipelands had Whomp's Fortress visible in the distance, though this has not been reported since. Enemies in this level have been reported to be Goombas, Whomps, Fly Guys, and Chuckyas.

Stars
The most common stars reported in this level are a 100 coin star, an 8 red coins star, and a star for reaching the top of a particularly large pipe. Other stars reported are finding a star in a "pipe maze", or activating a specific pipe that floods part of the level, allowing access to a star. Other stars have been reported, though these are unconfirmed.

BlackJoystick's Documentation
In BlackJoystick's Paint the Painting video, BlackJoystick uses the Painting Creator to access Skyhigh Pipelands, which is notably labeled as course ?. The first and only shown mission is labeled "The Great Pipe of the Sky". They select the mission, and enter the level. They platform through the level, which has most of the documented geography, including the only instance of a nearby Whomp's Fortress. Eventually, they reach the top of the largest pipe in the level, likely the Great Pipe in the mission name, and collect the star on top of it before the video ends.