Eigengrau
It is a visual perception occuring inside the eye, resulting from the isomerization of rhodopsin, a light-sensitive molecule in rod cells.
In complete darkness, eigengrau appears brighter than a starry night sky, indicating that the human visual system processes light intensities through contrast.
As children know, it is possible to generate entoptic imagery by applying pressure to the closed eyelids: the cells of the retina can be stimulated by friction as well as light.
The statistical images produced by diffusion models are evolved from noise patterns. Gaussian noise, specifically, produces a distribution of color intensities on the image plane that follows a normal distribution curve, resulting in a uniform grey tone.
All vision is pareidolia - all vision is discernment, identification from a chaos of intensities. The flattening into grey threatens the very ability to see. Reducing contrasts, closing the horseshoe.