Water Wolves

Next thing you tell me tooth fairies exist.

There is no shortage of tales and stories people make tell of monsters lurking in the dark. Most of them are merely that, stories made up to scare naughty children into obedience, and best be treated as such. With that in mind, let us talk of the Water Wolves because I guess someone thought making people scared of water would be oh so amusing.
So imagine, you wake up in the morning and get out into the village. Suddenly, you get wide awake - there are piles of water that look like wolf marks on the ground! Big paws, and they are inside the palisade area. So what do you think, that a stray wolf got wet paws when sneaking into your barn in the middle of night? No, because that apparently is too easy to deal with - of course that wolf was made of water! Why else would the paw prints just disappear, after all.
Can you see already where this is going? Yes, water wolves are supposedly this sneaky impossible-to-catch beasts made entirely of solidified water, free to return to that form any time they wish. Sounds scary as hell, would make for a true apex predator. And so some villages would go as far as to ward off their wells or even put a constant guard on it.

Basic Information

Anatomy

To tell you the truth, I do not exactly get how a bunch of water is supposed to take on the appearance of a wolf. Shape is one thing, but what about colour - is there dye in it? And even if it somehow does look like a wolf, how is it supposed to hurt anyone? Questions, so many questions.
From what few theories and stories I managed to gather, the idea is that anything goes through the water wolf like it would through, well, water. And that water will reattach itself right back, unless you put a cloth in the gap or something. Maybe put it in a bucket and boil that away? Not sure if it would work, but I guess getting stuck inside one such water wolf would not be a pleasant experience.
Interestingly enough, there seem to be two major types of water wolves in the stories. For the sake of simplicity, I shall name them Saltwater Wolves and Freshwater Wolves. The latter react very badly to salt and can turn back into a harmless puddle of water; the former cannot exist without it. Good luck guessing which one is about to bite you, I guess.