This is the strangest thing I've ever seen. My Adwords account has been paused for half a year, and today I looked at my Analytics account. I had 1 hit from "Google/CPC", for someone who looked at 12 pages. I clicked deeper into the results, and it came from my "General Campaign" and cost me $0.00. How is any of this even possible? Did someone from Google test something out? It's very weird...
Someone may have copied your tagged url from your AdWords ad onto a webpage. That happens quite a bit and can skew tracking. The Yahoo team actually copied one of my tagged urls and used it for listing a site in the Yahoo directory. The listing was nice but I've never been able to get them to update the url