The annual Pillow Fight in San Francisco took place a couple of weeks ago, and the footage has rolled in and onto the YouTubez. While the flashmob may bring to mind urban pranksters Improv Everywhere, the group isn't involved with this event, and perhaps that's because the whole thing seems kind of, well, violent. Still, it does look like a blast, but we just hope no one got hurt.

But judging by these videos, there had to be at least a couple of people who left with a bruise, right?