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.