Those fucking spiders. I've never been arachnophobic in games or in real life, but those spiders... and twice I've run into a room, not noticing that there was a giant one in on the ceiling. The first time, I went in, looted shit, realized spider sounds had been playing, and looked up. I froze and probably pooed a little. The second time it just fucking dropped on top of my and me sweat glands exploded.
And then, after I killed that second one, it glitched through the floor. This had happened before, so I knew in a few seconds it would shoot back up. It didn't happen for a while, so, leaving the corner I was hiding in, I moved toward the exit and HOLY FUCK FLYING GIANT NINJA SPIDER CORPSE RIGHT IN FRONT OF ME.