What's the worst nightmare you've ever had?

So, Flood 2.0, what's the worst nightmare you have ever experienced? When I was younger, I had a dream I was trapped in my living room, except it was pitch black, and all I could see were a pair of red eyes circling and stalking me for what seemed like hours. I finally realized it was a dream, but still couldn't wake up. Eventually I just stood up, and fell flat on my face, forcing myself to wake. What about you guys?