He’s not. He was put in the class accidentally
in chapter 4 page 17 when big sister was talking about missing kids there was a black head in the corner and one of the kids was (i assume it was the cat) looking at that direction so it is possible he was with the kids and can turn into an animal and his mom said they came there before when he was little. i am just putting the pieces together
Hmm that sounds a bit of a stretch, but I reread from the beginning, and i will say the MC thought of the sea (I’m ch 1) even though their hometown doesn’t have one. At the same time the kids went to “the sea” even though there supposedly is one. So I guess the idea that MC is also an animal isn’t too far fetch
If he is an animal, I’m going to guess that he is a mouse. It also kinda makes sense with the cat and mouse dynamic and mice are portrayed as shy too...