Riga, LV.
It seems somewhat hard to understand why are black holes being included in this list - for objects that by their definition cannot be observed directly, there certainly seems to be a whole lot of a solid observational evidence for their existence, both in the case of stellar and supermassive ones.
It should feel at least somehow wrong but it actually does not. Then again, I suspect that most "happenings" that include Hagrid could pretty soon end with a grave medical emergency of some sort, generating copious amounts of squick.
Luna/Draco/Karkaroff?
Oh yes, she can be. Even hedgehogs and porcupines can be, contrary to a somewhat popular opinion.
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