Here you can see an analysis of Nina's outfit when she arrives back from college.

Pictured above is Coco, a character from Animal Crossing. Notice the outfit similarity and Existence Of Ears™.

Now, from this indisputable evidence, we can infer that Nina and Coco are one and the same.

Here's where this really gets interesting. You may have noticed Coco's distinct lack of eyes. Well, the leading theory on this may surprise you.

That is right, it is believed that Coco's eyes reside within her head and only show themselves when she wants them to.

Now, how could this possibly relate to Nina? Well, you might notice that Nina has a mouth where her other eye should be.

I would like to propose that this is not in fact a mouth, but rather a facade, and that if she were to reveal her true form she would look something like this.

(Artists Rendition)

Day 216: Oh well that's reassuring because some of the parts of the fake people FLEW INTO MY MOUTH

cw for realistic/prop blood under the cut