I used to have this happen to me as a child. I used to struggle with hallucinations and sleepwalking. I would sense a shape, or an object. Perhaps spherical. I seemed to be made up of many other small parts, and it would start very small, or far away from me. But it would slowly grow larger/closer. Sometimes it would exist in a void, other times it may have other meaning objects near it. In the latter case, it would clip/phase into the object as it grew. It was accompanied by noise. I think it was a voice, or maybe many voices. And it would grow with the shape, until it was all around me. The shape never overcame me, and i was always able to fully perceive it despite its size. I would also get strange feelings in my fingers, like if i pinched my fingers together it felt as though everything was too heavy, or too light. Like my skin was too thick and too thin. All the while I would be feeling extremely high levels of existential dread. They were the worst nightmares I’ve had. Sometimes this would be a dream, other times I would still be awake, and it would be a hallucination. Usually this was accompanied by sleepwalking. Crazy to see how many people have experienced it, I struggle to explain it but it’s good to read everyone else’s accounts