There is one method of interaction that has been reported often enough to document.
It is not guaranteed.
But it has been repeated.
A stone is selected.
It is altered — not for function, but for attention.
Paint, markings, attached objects, or any other form of decoration may be used.
The purpose is simply to make the object stand out from its surroundings.
The individual then holds a wish. This may be spoken aloud or kept entirely private.
The stone is then placed in a quiet outdoor location. Most commonly near riverbanks, trails, or undisturbed areas.
If the stone remains where it was left, nothing further is known.
If the stone is gone upon return:
It is believed the Mudmen have taken it.
There is a persistent belief that, in such cases, the wish receives what has been described as:
river luck
Do not leave more than one.