Zombies are having a moment. It seems like that moment has been lingering for a while, but the zombie thing hasn't faded away yet. The Walking Dead's ratings and the view count for World War Z's trailer are proof of that. Apparently, so are rising sales figures in the firearm industry. On Black Friday, there was a 20-percent hike in background checks for guns over last year. Some say that the zombie culture is a contributing factor.