Not sure, how old I was, probably 10-12. This one isn’t so much classic nightmare, but left me extremely unsettled for weeks and still gives me the heebie jeebies when I think about it.

In my dream I was at an event for returning space shuttle astronauts who had just landed. Apparently there was some major problem during reentry, and most of the crew didn’t make it, but one had barely survived. When they brought out the surviving astronaut for an interview or whatever, the dude was literally just a naked human nervous system in a NASA spacesuit. Where his head would have been was the classic anatomy textbook image of just the brain with eyes floating in front of it, supported by a spinal cord. No bones, no muscle, unable to talk or anything. I remember the head was gently bobbing from side to side a few inches, and every so often the “head” would just rapidly spin around a few revolutions, then stop and continue bobbing eerily.

This is pretty much exactly what the dude looked like in my dream https://img-new.cgtrader.com/items/2443319/bd71a87570/large/nervous-system-and-dura-matter-3d-model-low-poly-fbx-gltf.jpg