It's inevitable for details to change when translating a book to the big screen. Directors and their respective distributors have to target their audience, and that sometimes means toning down certain elements of a narrative in order to reach more viewers.
New concept art from Jody Revenson's book Harry Potter: The Creature Vault
reveals that the Hollywood franchise could've been a lot darker than what was released. Granted, the films' ratings increased from PG to PG-13 when the fourth film rolled around (except for The Half-Blood Prince
, which oddly received a PG rating), but those ratings would hardly allow for some of these creatures to come to fruition.
The Dementors are more Grim Reaper-like than the diaphanous beings audiences meet in the third installment. Fenrir Greyback, the wizarding world's most savage werewolf, looks more like a demon wolf than the brute with sharp teeth we see in the films. And, Nagini? Nope. Nope. And, more nope.
The following 10 sketches are what fantastical nightmares are made of. (USA Today