Wifwolf

This shapely creature was a human once, but she prefers her new form.

Currently, she hunts on the outskirts of civilization, uninterested in spreading her curse. But she is quite interested in humanity, both for companionship, and food. Her personality is actually very playful, and she won't turn down a friendly chat.

The fact is that she is built to hunt humans, both to eat and turn. However, because it takes only a nick from one of her teeth to pass the curse on, her teeth are arranged in such a way that they won't tear skin easily unless she really tries.

Her variation of the werewolf curse gives the victim nearly complete control over their form, which has spelled the doom of many careless wolves who bit down and had the tables turned on them by their quarry.

As for how her stomach works, it's quite stretchy and it's processes can be controlled to a point, although transformation will immediately melt down it's contents directly into energy.
Well, that's one take on her anyway. There are also lycanthropes of all ages still living normal human lives... but who'd love to cut loose one of these days.