[ He doesn't know much about gods manifesting solid forms, but there does seem to be a common theme. ]

Potentially... body parts. Cursed ones. [ It's a recent theory that he's not overly fond of, having hoarded a tongue in a box for months on end, but it would make sense how the dark water has shown up everywhere they've gone. ]

It's possible. Or if it's important enough, word will get to the town criers. Otherwise it might take some asking around that could garner suspicion.