Trope-a-Day: A Glitch in the Matrix
A Glitch in the Matrix: Avoiding this sort of thing, when it comes to virtual reality, is one of the few legitimate uses for the Out-of-Mind visual textures. (Others mostly including hiding gifts and playing really terrible practical jokes.)
A more commonly seen variant are “weavespiders”, small metallic fractal spiders (which everyone knows to ignore) used in virtual realms to collect trash, reassemble broken scenery, and otherwise do maintenance. While, obviously enough, this can simply be done programmatically without requiring any visual metaphor, reifying them like this is a simple way of avoiding the uncanny valley effect of changes “just happening” with no apparent in-world cause.