By Patrick Kevin Day

As far as monster flicks go, zombie movies are like snowflakes -- no two are the same.

Frankenstein movies are inevitably about the dangers of technology run amok, vampire movies are almost always about sex, and you can't make a werewolf movie without saying something about the duality of a man's nature. But zombies can be whatever the filmmakers want them to be.

Commentary on class inequality? Zombies can do that. Commentary on the shallowness of the modern lifestyle? Yup, yup, zombies can do that too. And zombies can even work on our behalf, demonstrating just how brain-dead some teenagers can be (and taking care of them in ways we never would).

With the eerie "Walking Dead" back on AMC for a second season, it's a good chance to examine the many ways zombies have been used to point out the flaws, foibles and quirks in our society.