Oops, I think you touched a nerve there, thejarofweirdthoughts.

Tess is an extremely high-level monster. Like, end-boss level. This is due to the particular combination of effects of her curse, which has the end result of confining her to a small box, but giving her complete and utter control over that bailiwick. Basically, if you get in that chest with her, you're done.

Tess is incredibly strong and durable; a sword will bounce off of her harmlessly, and she could easily snap that same sword in half with two fingers. Though her fur and skin are still soft to the touch, striking her is like striking metal; it's as though Tess has become the treasure she's guarding.

On top of that, the strength of the curse on her also creates a magical field that causes other spells to fizzle or go otherwise awry. Outside magic won't work at all inside the chest, and trying to cast a spell on her from outside usually results in the spell weakening or diverting before it gets to her. In theory, it could be possible to un-enchant her, but it's difficult for a mage to unravel another mage's spell, and the mage that cursed Tess is long dead.

So, it would take something extremely powerful to even put a dent in Tess.

This is balanced by the fact that Tess can't leave her box. She doesn't have many options for ranged attacks other than throwing treasure at someone (potentially effective due to her strength, but she doesn't like doing it, and if she knocks someone out, she has no way of retrieving the body.) So as long as you keep out of reach of her arms, you're good. Tess' prey are mostly adventurers who either get too close without knowing she's there (because the box is closed) or who want her treasure and don't think she's a threat. By the time she has a hold of them and they realize their mistake, it's too late.

Now, I believe Tess would like to get back to digesting that meal of hers. And we should probably give her some time to cool down.