Crogs are the magical, skeletal crocadile species that swam in the School for Boys' waters during the second book of the series. They are now extinct.
Crogs were not much to describe, simply being crocodiles completely made out of bones. They are a lot like Stymphs, which are the exact same thing, except not crocodiles, but large, skeletal, birds.
Behavior at School Edit
Crogs swam in the waters of the School for Boys. They were a special species that would only attack females and only nip at passing males. Crogs are obviously all males, or else they would constantly be ripping each other to shreds.