Very similar to indigenous 'totems'. Which can be almost anything. Interesting programme on the abc a couple three years back, I think off the top of my head it was Conversations with Richard Fidler. A woman with fertility issues went to stay in NT due to husband's job. She was bored and started talking to the local people. They took her swimming at a secret women's business waterhole, and she felt something wriggle inside. Shortly after she discovered she was pregnant, considerably against the odds. The local women assured her that her proto-baby had a totem - which was a striped leech and that the waterhole had given it to her. Never heard about any followup, but I think maybe this sort of thing might resonate with your comment. I have no information about how true this story was, but the abc are usually pretty good at fact checking. So probably not a wish fulfilment thing.

Also some poor fucker ending up with a witchetty grub, or some other weird insect.

On the other hand, they can shapeshift, and their chosen form is usually one that fits you personally, so I doubt that someone who ends up with a weird bug would mind too much. At least until someone tries to relocate the weird bug outside, or accidentally treads on it.

It's the clumsier people accidentally slamming their daemons in doors that might have a worse time. Getting your finger or hand caught is bad enough, injuring a physical manifestation of your soul probably hurts a lot more.

and someone would have a white butterfly