In real life, when someone crosses you, you usually grin and bear it or simply move on. But not in the movies!

The smallest slights can lead to the largest feuds and, before you know it, people are dyeing each other's hair blue, rigging up buckets of blood, and pulling all kinds of dirty tricks in the name of revenge. Here, then, are some of the most memorable movie feuds, from the cartoonishly comic to the scarily sadistic.