Amp Cavern

Amp Cavern is an anomalous level found in some personalized copies of Super Mario 64, often reportedly located on the Fourth Floor of Princess Peach's Castle. It has been described as a large cavern with several Amps, reportedly using the unique Amp behavior found in the pyramid of Shifting Sand Land as well as the standard enemy behavior, as well as several other enemies resembling Amps such as Keronpa Balls. The level's theme is reportedly rather unique, being a slower remixed version of the castle theme from the original Super Mario Bros. video game for the NES.

Description
Amp Cavern is described as a dark and expansive cavern consistently very hard to traverse, and players often get lost inside of the level. It also contains several bottomless pits. It is filled with Amps and objects such as stalactites, stalagmites and crystals for Amps to circle around, as well as holes in the wall for Amps to appear from using the Amp behavior only seen in Shifting Sand Land. Other enemies such as Keronpa Balls and cave-based enemies such as Scuttlebugs have been reported to appear, though much less frequently than Amps.

Amp Cavern is a unique level because it appears to consist of a set amount of Procedural Generation instead of going on forever, though it does appear to generate a significantly large amount of areas in the level, with some examining associated code and finding that the level appears to generate based off of a seed associated with a save file, though this is not yet understood as some code does not appear to be present, likely hidden similarly to the Personalization A.I. itself.

Missions
The Power Stars of Amp Cavern are inconsistent, though a specific process appears to occur related to the level's missions. Several random rooms appear to be generated once and never again in the level, often related to the level's missions in some way, shape or form, likely due to most of the level not accommodating for Power Stars, requiring the A.I. to generate specific rooms for Power Stars. The most common types of "mission room" usually require the player to go through a maze, often being the 8 red coins star, or reaching part of a room containing an object that must be opened or broken to obtain the Power Star.

Theorizing
The fact that Amp Cavern appears to be a set amount of Procedural Generation indicates that the anomaly is not fully understood, as Procedural Generation was previously only known to go on infinitely. Alternatively, instead of being Procedural Generation, the level could just be mass amounts of Dynamic Level Arrangement, despite being a larger amount of DLA than previously documented. The fact the painting appears to be a different art style than the rest of the paintings in Super Mario 64 implies that either a different person or group created the paintings, or that the painting was created in an earlier state of development for Super Mario 64 when there was a different art style. A third theory suggested to be an explanation for the different art style is that it was somehow created by the Personalization A.I. via a currently unknown system, though this theory is heavily debated and lacks evidence.