The worst nightmares are the tactile ones, where I can feel something that happens in the dream. You cannot prove to me that other worlds don't exist so long as my dream universe remains real enough to touch me.
I can't recall most of the first dream anymore (it's been awhile since I woke up), but at the end I was very much aware that I was dreaming. Everything had gone monochromatic, in shades of red to black. I knew I needed to get out of this nightmare soon, but I had turned and there was a table with a bunch of clutter on it, and everything was blurry. I couldn't see anything clearly in the dream, as if the red light was also a haze. Something on the table had caught my eye.
It became clearer and clearer as I approached, but there was something still about this mystery object or objects I felt was important so I went to pick something up off the table, to inspect it or maybe to read something off written on it. As my hand stretched out before me, there was the impression of a dark shadow behind me. For a moment I stood above my dream body, with the awareness that the silhouette was going to impact me in some fashion, then I tried to step aside but it was too late. We collided and this thing ghosted through me, insubstantial but still harmful.
When I woke, the entire left side of my body where the creature or person had passed through me was both tingling and somewhat asleep. I was laying on that side, but I've never had half a torso fall asleep and then wake up before. The briefest thought, "stroke" passed my mind before I replaced it with "nightmare" and tried to wake AgtOrange, who didn't stir the slightest at anything I did. So I did my best to curl up close with my back to him and fall asleep again, hoping that near proximity of another human person would stop any more nightmares. I was not so lucky.
I remember that much of the second nightmare involved trying to find dry land while traveling through a swamp, one potentially full of hazards in the water. And hopping or floating, not quite flying (I can never fly in my dreams, only take extended hops) as fast as possible to get away from something that could only swim, while searching for a safe place to rest.
There's a gap in the dream, which I've forgotten, but it ends with me in a crowded room of people, and this guy walks up to me and grabs my ass. And it felt like the same electricity from the first dream; I woke instantly with the bottom of my right glute feeling like I'd been hit with a TENS unit and almost burning. After that, trying to sleep just felt pointless.