Bowser's Brap Barn

Bowser's Brap Barn is an anomalous level found in some personalized copies of Super Mario 64, taking place in a farm level filled with the poisonous gasses seen in Hazy Maze Cave, apparently being Bowser's farts. The level is commonly described as one of the most complex anomalous levels documented. It reportedly is only completed by people with a strong willpower. This level's music can be found here.

Description
Bowser's Brap Barn is commonly describes as a grass level similar to Bob-omb Battlefield with the titular barn on top of a hill in one corner of the level. The level is also covered in gas, with several high points where the player can recover health, with the most gas in a certain area with a bottomless pit that contains platforms with red coins that the player must collect before dying. The level also reportedly has a water tower with a sub-area containing a Power Star, surrounded by a moat with a hidden pipe leading to the Round Aquarium. The barn also has a pipe that leads to a factory creating farts with a Big Brap-omb boss fight, holding another Power Star. There is also a special door that leads to Bowser in the Shower, and a hidden hole in the wall similar to the holes in the Jolly Roger Bay room of Princess Peach's Castle leading to the Secret Aquarium that lead to Bowser's Big Bean Burrito. There is also a cave behind the wall that leads to Fart Cap in the Toilet Trial, and a floating island resembling the one seen in Bob-omb Battlefield with another Power Star. The level also reportedly has a Bowser boss fight, though where is not specified.

Unique Enemies
Several unique enemies can be found in this level. The Brap-ombs, reskins of Bob-ombs to be made of farts, Braphogs, large pigs that excrete more gas into the level that will either run around aimlessly or charge at the player, Poop-Balls, reskins of Big Steelies to be made of poop, presumably from Braphogs, and Fart Fruits, apples that drop from trees throughout the level that explode into gas.

Bowser's Big Bean Burrito
Bowser's Big Bean Burrito is a level made up of a massive rotating cylinder with several pieces of food sticking out similarly to the rotating pillars in Super Mario Sunshine's hidden levels that has 8 red coins scattered throughout the level. Collecting all of them unlock this level's Power Star, though there is also reportedly a star for finding a way to enter the burrito itself.

Fart Cap in the Toilet Trial
Fart Cap in the Toilet Trial is a Cap Switch level found in Bowser's Brap Barn. It is a large cavern with a massive toilet in the center. The player has to use the Fart Cap, an anomalous cap that allows the player to survive poisonous gas, and even excrete it to damage enemies and have a higher jump (potentially the predecessor to Wario's hover fart ability in Super Smash Bros.: Brawl), to get around the level and flush the toilet, which will cause it to release the Fart Cap Switch, a light green switch similar to the Frog Cap. It also reportedly has an 8 red coins star.

Missions
Wait, I already mentioned most of them. Oops. Okay, I'll reiterate the ones. There's one in the water tower, one for red coins in the weird pit area, one for beating the Big Brap-omb, one for collecting 8 red coins in Fart Cap in the Toilet Trial and Bowser's Big Bean Burrito, though those are technically separate areas, and there's also a Power Star on the floating island. My notes say there's also a star for getting on top of the barn, finding the key to a locked room in the barn, finding 5 secrets, and somehow hearding the Braphog enemies. I hate this level.

Theorizing
This level may have been the prototype version of Hazy Maze Cave, due to the obnoxious amount of poisonous gas, the Poop-Balls that may have been carried over as the boulders, and the well-known theory that Hazy Maze Cave is either a sewer or the castle's septic system. Said Poop-Balls were supposedly relocated into Hazy Maze Cave and then solidified according to some signs found throughout the level. This level's origin is speculated to have been from Bowser eating Bowser's Big Bean Burrito with Princess Peach after kidnapping them, causing them to have mass amounts of flatulence.

This level also seems to have some sort of anomalous connection to the people who play it, similarly to the original description of the Personalization A.I., as this level reportedly only appears to people who hate their life. How it reads their minds is uncertain, though it may be an advanced deduction based off of their controller inputs.

It has also been speculated that the level itself is inside of Brazil.

Anomaly Warding
It has been reported that several anomalies do not appear in Bowser's Brap Barn, such as anomalous enemies seen in other levels, Dynamic Level Rearrangement, and even malevolent anomalies that can chase the player such as the Wario Apparition, likely due to this level's disgusting nature and mass amount of farts.

Coin Hell
The level will randomly fill with coins and crash the game. I was looking at my old page on my knockoff MIPS Hole page for a lot of info here since I did research throughout the Discord server for both MIPS and the original lore to make the page a definitive documentation of Bowser's Brap Barn and I don't know if I just made this up or if this is a legitimate thing someone said.

Princess Peach
This level has a strange amount of connections to Princess Peach. Peach has reportedly been mentioned in signs around the level, and may have even been tied to the creation of the level if the theory is correct. Notably, if Peach is unlocked as an Unintended Playable Character, they can supposedly use the Fart Cap to transform into one of the Braphogs in the level, though this was likely made up by a troll because that's too disgusting for Nintendo to have considered adding to the game. So is this entire level, actually. It's almost as if it's a big inside joke.