So, maybe about 10 minutes ago I'm sitting here at my computer with my headphones on (wasn't listening to anything yet) and the sky is a bit dark and gloomy as if there is a storm not far away. As I'm browsing through another thread, I see a big flash in front of my eyes and there is literally a lightning strike/thunder blast that sounded like a cannon and not only did it surprise the hell out of me but it scared both of my dogs as well. The only other time that happened to me is when I had my headphones on and heard it through them, but that time I was listening to music and so most of its sound was drowned out. Oddly enough, I just checked the radar and my area and there is a storm but the more severe part is not going to hit us because its farther south.

That gave me the inspiration to start this thread.. what has in the past surprised you from being so sudden or scared you?

A Dreugh in a pool in a cave during an early Morrowind playthrough. I was underwater, I turned around and he was right there in my face.
I nearly jumped out of my skin I was startled so bad. I'll never forget that.

That happens a lot in Bethesda games it feels like. They all get you used to some battle music before the enemy actually makes contact with you, and then sometimes enemies will sneak up on you with no music cue.

Having a liesurely stroll in Fallout 3 and then turning around to DEATHCLAW TO THE FACE always makes me jump.

Or Yao Guai.

Or Mountain Lions in Oblivion.

It was when the first drought hit and we had really bad bushfires, and there was smoke and a massive wall of dust that had blown up from another state and as the weather had changed and the low was heading in this direction basically as far as you could see left and right and it went up into the sky was a huge wall of dust but one side was hot and the other side was cold as the low front was the leading edge of the dust cloud, and standing in front of it as this huge wall just blotted out everything, then it passed over me, and there was only limited vision and going from 42 c to 20 c in a few minutes, i knew what it was, but had never experienced anything like it, it was really incredible but somewhat overwhelming.