I don't look anythin' like a troll, thank you very much. If anythin' I'm some form of fish. See here? [He points a clawed finger at a fin as it wiggles.] I've also got gills, I've never seen a troll with gills.

[He exhales loudly, can you tell he's over this? All of the sighing, honestly.]

I don't generally look like this. I'm normally a human, only magically inclined. A wizard. You're at Hogwarts school of Witchcraft and Wizardry and you are indeed a student here.