Cujo (1983): Man's best friend becomes his most fearsome, furry enemy in this thriller based on the Stephen King novel. The name alone is so synonymous with killer canines, it's become shorthand. And it's not like some yippy, annoying dog that turns into a monster, like a Yorkie or a Chihuahua. No, this is a friendly, lovable St. Bernard, a breed that's traditionally been known as a reliable caretaker, who goes wild after he's bitten by a rabid bat and wreaks havoc on a small town. It's sort of a squeamish thing, the idea of having to fight and take down an animal that's traditionally considered a family member, but "Cujo" suggests that primal survival instincts will always win out in the end.