Quin

Quin is the name of an anomalous Toad found in some personalized copies of Super Mario 64, characterized as a Toad with a different color than the regular Toads seen in the base game of Super Mario 64, most commonly yellow or green. Quin earned it's name from the most common name given by the Toad when interacted with. Quin is one of the few dialogue-based anomalies, being characterized with gibberish dialogue and/or the potential ability to influence the game with dialogue.

Behavior
Quin has 2 main behaviors, both commonly taking place one after the other, though can reportedly be found without the other in some copies. The first behavior is relatively basic, simply having gibberish dialogue, either being entirely random characters or nonsensible strings of words. These have reportedly slowly become more and more coherent every couple times Quin has been interacted with, though never appear to become fully coherent when this behavior appears on it's own. The secondary behavior appears when Quin does not speak gibberish, where anomalous personalization will occur depending on something Quin says, such as Lethal Lava Land's lava color changing to blue, or a new level appearing in place of another level, such as Bob-omb Battlefield being replaced with Bob-omb Village. Notably, anomalies related to other anomalies such as the Internal Clock and Internal Weather System have also been reported to be mentioned by Quin. It is not known if Quin causes these anomalies to occur, or simply indicates the existence of these anomalies.

A minor anomaly that has been documented to occur with Quin is that they can disappear upon being talked to, only to reappear when a certain amount of stars have been collected, potentially multiple times throughout the game. This appears to be similar to how MIPS the Rabbit functions, implying a connection, though this could be a coincidence.

Theorizing
The common theory about why Quin speaks gibberish is that they were a test NPC meant to test how the Personalization A.I. could write dialogue, and when Quin is reimplemented, that gibberish dialogue is remnants of those tests until it was refined enough to be able to write legitimate dialogue for NPCs. However, this does not explain the other anomalous properties of Quin, which are currently still debated.

Some have theorized that Quin influencing personalization was a remnant of a scrapped "event system" where special events occur throughout the game, with Quin indicating these events occurring. This could also explain why Quin has been reported to only appear when a certain amount of stars have been collected.

Another theory about why Quin talks about the existence of various anomalies is that Quin would serve as a indicator for developers of the game; letting them know how the AI was modifying the game. According to this theory: the reason that Quin speaks in gibberish dialogue is because, due to the AI being unstable and unfinished, Quin cannot parse what the AI is doing and therfore cannot inform the player of it, so it generates gibberish when spoken to.