Active Geometric Aberration

Active Geometric Aberration (abbreviated as AGA) refers to a specific type of anomalies that appear in stages within Super Mario 64, more specifically the geometry of the stages. These oddities are activated while playing in the stage and would provide trouble for players of the game. Effects caused by Active Geometric Aberration include altered width, height and depth of geometry, rotation, and different collision variables.

This type of anomaly can be compared to Dynamic Level Rearrangement. However, the differences between both types of phenomena would be that DLR affects only objects, textures, text, and music, and is done before the stage is loaded in. On the other hand, AGA can only alter the geometry of the stage and can be done while the player is playing on the stage and before it.

Alterations
The specific alterations caused by Active Geometric Aberration can occur in stages, so long as the stage itself contains level geometry. Along with this, the phenomenon cannot add any parts of geometry, but can remove parts of the geometry and/or alter the placement of them.

One of the notable types of alterations caused by Active Geometry Aberration would be the size of parts of the stage's geometry. This alteration can shrink, grow, or stretch parts of the level itself. It can modify parts of the size of the polygons of level geometry, and chunks of the level could be altered in width, depth, and height. Parts of the geometry that connect to each other can have different alterations, resulting in some parts looking "pinched" or warped. Some parts of the level are reported to look jagged and corrupted because of this.

Rotation can be added or removed in some parts of the level's geometry, including platforms. The speed and axis of the platforms can be altered to any type, which can result in oddities surrounding fast platforms and tilted geometry that occur in specific parts of the base game being found in other places. Lesser known versions of Active Geometric Aberration have been reported to only occur in platforms in stages, but other reports state that larger chunks of level geometry rotate.

Collision of level geometry could also be altered to provide trouble or surprise toward players. Types of collision include lava, enemy touch, normal, quicksand, and no collision at all. This can result in odd scenarios as walkable lava and "phantom platforms", which could be seen as unfair or cryptic.

Some platforms and parts of level geometry have been reported to move around when they're not supposed to in the base game, with some heading towards specific patterns. The speed and path of the geometry through this alteration can vary as well, resulting in many bizarre scenarios. Parts of the level can be removed or placed in different places to provide trouble for players as well.

Speculation
With no doubts, Active Geometric Aberration is caused by Nintendo's experimental A.I. and is an effect of it in copies of Super Mario 64. Due to its' similarity towards Dynamic Level Rearrangement, it is most likely possible that AGA was based off a similar concept towards it or vice-versa. The purposes of AGA could also be similar to DLR; as a way for the game to challenge or make stuff easier for players. However, the drastic and "corrupted" looks of some of the results of AGA would make this a bit doubtful.

It could also be possible that the odder results of Active Geometric Aberration were caused by the bad side effects of The Self-Patching Anomaly in some copies of the game. The Self-Patching Anomaly could have corrupted some parts of the algorithm of AGA, in which corrupted versions of the level geometry would surface in playthroughs.