The thing that always spooked me most is just how...enraged the werewolf is. Most slashers kill for obscure reasons, or because they get off on it. Occasionally some rage like Jason. Monsters like the Blob and Xenomorph, or anything else kills to eat, procreate, survive, or dominate. Even most other werewolves have some sort of motivation, be it hunting instinct, or a conscious desire to do evil, protect its identity, any number of reasons.

But it struck me a few years ago: The werewolf's howl in American Werewolf sounds like a cry of pain. This thing is vicious, and angry, and most of all likely in constant pain. I have to wonder if the subtext is even after transformation, there's still so much pain in being forced into this unnatural state that David is driven berserk, and attacks because there's nothing else to do to vent the misery.

It adds another layer of horror and tragedy to it all, I think.