@velsy Consider that she's a cute fat fish monster normally, but when she actually fights(or eats in this case), the cute fish turns into a really, really horrific long-mouth devourer with exposed tendons in the jaw and everything.
There's indications that the cute one is not what she actually looks like, and something is keeping her form "reigned in". I recommend continuing reading, because things get pretty interesting, the last few chapters are really something.