Something odd...

[Chao. Enterprises]

Many years ago, my sister had a Fly/Dark chao named Jade. It was the best chao she ever made, and she was pretty dang proud of it. Then one day, when she went into the chao garden to go and see Jade, she was gone. Then she thought that maybe she was in the school. Nope. Then she checked the other 2 chao gardens. Still nothing. It couldn't've died, as Chao don't age while you aren't around. Even if it did die, it would've reincarnated and left an egg as my sister took good care of her. To this day....we still don't know what happened to her. I'm not allowed to use her memory card, and nobody but me, her and my big brother play the game. My brother has his own memory card as well. It just...vanished. How could this have happened? We've been stumped for some time about it.

[chaoadventures]

This happened to me too one time. Except it was an (as far as I remember) unnamed Mono-tone Red Dark/Normal chao.

"I never did see those pants again"

He just disappeared one day. Actually, that was so early in my chao raising days, that I hadn't been there long enough to see a death/reincarnation cocoon before,
so he couldn't have died while I wasn't looking.

I think he was on an orange MadCatz (2nd worst GC memory card on the planet too.) memory card, which I still have today (and sometimes use), with all of the gardens unlocked and currently full.
Definitely never found him.

[Chao Professor]

Something like that happened to me too! Can you remember if all the gardens were unlocked? Since it was a dark fly, try and remember if the hero garden was unlocked. Pebbles was my absolute favourite chao, then one day, she vanished. I found her weeks later when I opened the dark garden. You see, when a garden has more than 8 chao, a chao will be pushed into a different garden. Pebbles was pushed into the locked dark garden, which explained how she vanished. Or, perhaps Jade was transferred to the Tiny Chao Garden, was picked up, and then your sister forgot to save. That's a serious glitch that deletes your chao. That's all I can think of, really! Poor Jade!

[Chao. Enterprises]

Something like that happened to me too! Can you remember if all the gardens were unlocked? Since it was a dark fly, try and remember if the hero garden was unlocked. Pebbles was my absolute favourite chao, then one day, she vanished. I found her weeks later when I opened the dark garden. You see, when a garden has more than 8 chao, a chao will be pushed into a different garden. Pebbles was pushed into the locked dark garden, which explained how she vanished. Or, perhaps Jade was transferred to the Tiny Chao Garden, was picked up, and then your sister forgot to save. That's a serious glitch that deletes your chao. That's all I can think of, really! Poor Jade!

We don't have GBA connectivity and all gardens were unlocked.

[Crazo3077]

So I have a thought on what causes this, but it entirely speculative and hard to explain, so I'm gonna try anyway.

So we have the three gardens and each has 8 Slots, but if I remember correctly from playing with the code of Sonic Adventure DX, each Chao is locked into one of 24 Slots, and that slot just changes what location the Chao is in, as opposed to being listed as in a slot per garden. So a Chao will be in Slot 1 or Slot 2 or so on, but also be in a specific garden's queue, which has 8 slots, so Queue 1 or Queue 2 or so on. [Note: I am uncertain how the queue system works for gardens, whether it is the Chao that was most recently brought to the garden takes up Queue 1 and everyone else is pushed back, or everyone is randomly assigned a position in the queue, but I will assume the former, solely for ease of explanation.]

So let's say we have two Chao: CHAOSKY and ROSSO.

CHAOSKY is currently in the Dark Garden, and is in the eighth and final queue, as the garden is full. ROSSO is in the Hero Garden. You decide to move ROSSO to the Dark Garden, which moves CHAOSKY to the ninth in the queue, pushing him out of line. This should transport CHAOSKY to another garden, most likely the Hero Garden.

This is my first potential solution: If CHAOSKY was dying, but you did not know CHAOSKY was now in the Hero Garden, you may accidentally let him die in the background without being noticed. This is the most realistic possibility, because it uses a situation that we can recreate and locally follow.

More speculatively, I think there could be more than 24 Slots for Chao. It may be possible that there are 26 or possibly even a system that allows for an infinite amount of Slots to be created. The problem would be that the code that moves the Chao from a garden's ninth queue to a different garden may not be perfect. There may be some issue with moving the Chao that sends them to some incomplete fourth garden that is inaccessible. Thus, the Chao cannot die, but it also cannot ever be retrieved unless we could access the data and confirm the Chao's existence. This is more speculative because I currently have no way to confirm that this is how it works.

Those are the potential answers I offer, and hopefully that gives some sense of closure.

[Chao Professor]

^ Awesome, Crazo. Although just speculation, you provided a very possible reason for a problem that's been posted around here quite a few times. So even though though I've never experienced the problem for myself, you have my thanks.