Quin

Quin is an anomaly where in certain personalized copies of the game a re-colored toad NPC, usually of Yellow colors but can vary in copies that have the anomaly, can appear in the basement. The name was given because in text where it states it's name, it is almost always Quin. It only appears if you have less than 20 stars. If you do speak to it, it will reappear at later stars.

Behavior
When first spoke to, it will speak full gibberish, and after speaking to it you can't speak to it again until you get 26-30 stars. Any higher will cause them to not appear again, even if you do a new save file.

If you speak to it when it reappears at 26-30 stars, it will speak slightly more fluently, but is still gibberish. It can make words now but only 2 letter words usually. Once again after speaking to it you can't speak to it again until it reappears at 31-35 stars.

After speaking to it for the third time, it can make full words, but the sentences still have no meaning and are usually stuff like "Cow, dog nice win, Mario you ten star" By random chance you can get sentences that make sense, like "Hey Mario! I heard that painting has a secret star!" But the sentence usually doesn't actually put a secret star in one of the courses, due to still only being the third time you speak to them.

When they reappear for the fourth time at 36-70 stars, the sentences have a much bigger chance of making more sense, and can actually change the game based on what they said. Though if the sentence doesn't really make sense like the rare times it happens, you just get an extra life.

The fifth and final time you speak to it at 71-120 stars, all of the sentences make sense. You can speak to it without it becoming impossible to speak to after speaking to it, and the response is different every time. This is when Quin will start saying their name and changes can sometimes be drastic. The changes are usually positive and the few times it is not just include Mario's hat getting blown off after reading the message making it slightly tedious to get it back, or a life being lost suddenly without a death screen. The only time the negative change was really bad was when Mario got a game over without warning long after reading the message.

Report #1
''I was just trying to play Super Mario 64 and when I got to the basement there was what appeared to be a Yellow Toad to the right of the Toad usually in the basement. I went to talk to it only for the text box to just be random gibberish like "ASjfa, jiowq.b at-ar /--_wr yergertg et= trehue" and "Adjagbat378wy8234-2-234 2= 2 4r2trgfq231#@$534" and after the text box closed it I couldn't speak to it anymore. Later after getting 26 stars I noticed it was back. This time it said stuff along the lines of "Ya th grha it fhauirte me ahreui hi hauigthie" I could definitely spot words there. They were only two letters long though. Once again I couldn't speak to it anymore and just went on again. I didn't check again until I had 35 stars. It was once again there and this time it made sentences.This time it said "Wow maybe hah just can't time move instant" I didn't know what was going on! It kept getting more fluent every time it reappeared! I got another star and checked the basement again for it an it was there again. This time when I spoke to it, it said "Mario! Thank goodness you are here! This rabbit has been running rampant! I think there may be another one because I could almost swear I saw two of them at once!" After they said it the rest of the text box just became nonsense again "How maybe. This." But after re entering the room there were two rabbits. After catching the second one it told me "Hey! Leave me and my husband alone! He told me all about you and why he was late for the date! If you take this star will you?" Afterwards a star appeared. It shocked me because this never happened last time I played. I was curious to see when it would finally come back. It didn't come back until 71 stars. When it spoke though it was completely fluent this time. This time it said "I sense a bad omen Mario... I think something really bad might happen soon!" Later I got a game over while trying to fight Bowser. I never even died and I had about 5 lives left. Was this the bad omen they were talking about? Later I went to talk to them again to see what it would say. This time it said, "Hey Mario! It's me! Quin! Lately, there has been a strange fog in every stage! I wonder what it could mean!" After talking to them I went into a stage and there was indeed fog. It seemed to do nothing though. I just was bored of talking to it and just went to the Bowser fight again. I won the fight and stopped playing because it was late and I needed rest.''

Report #2
''I think my copy may personalized you know! I was just having a good time, playing Mario 64, collecting coins, just all of a sudden there was a weird Green Toad in the basement! It just said nothing interesting! Just, I kid you not "HTUIeiufnuiergieurhgiuehierhir" It looked like someone had banged their head against the keyboard several times typing its dialogue. I couldn't even speak to it anymore after speaking to it once! I tried looking on all sorts of wikis for this strange thing but they didn't appear anywhere! And after going into a course it just disappeared! Later, it came back. I think there were two letter words, but I can't really remember that much. It then reappeared again, and it made real words this time. I remember it said "You. Hello! Mario run, money" I am not sure if it meant anything, but it probably didn't. Once again after unlocking the third floor, I was trying to get stars from the basement to get the 70 required to get past the infinite stairs. But it appeared again! It creeped me out this time that they said "Mario! Is that you? Oh my! Well... I heard that you can spin after a triple jump! Try it!" Afterwards Mario gained the ability to spin after a triple jump. I didn't get what happened. Later, after getting 120 stars and exploring the castle again after getting bored, they were indeed back once again, and told me, "Mario! I never did tell you any of our names... Well that is because we don't have any! But we do give nicknames to each-other. The nickname I was given was 'Quin', cool right!" Apparently Toads don't have names. Just nicknames. I also noticed all of the Toads in the castle actually told me what their nickname was! In fact, even though I got all of the stars, one of the toads had one extra star. It didn't seem to do anything except make my star counter go up until I checked the top of the infinite stairs. It appeared the Bowser painting had a door now, that said 121. After opening it, it seemed to lead me to a "Fourth Floor" I actually was surprised because up there were 4 more courses. After collecting all of the stars there, I had about 150 stars, because there was also a secret star there from one of the toads. I felt satisfied because this seemed to be all that would be added since Quin's dialogue didn't do anything anymore.''

Theory
The only theory of what it could be is that it might be an NPC made as an AI testing ground, for the developers to see its capabilities with text boxes. It might have been left in because either the developers forgot to remove it completely or they kept it in due to not causing any really bad effects.