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Hmm, I think more context is needed here to trope this; there are a ton of radically different things this could be.
What genre is the work? (scifi, fantasy, etc.) Was this someone they know? Was it a dead somebody they know, or a live somebody they know? Was it trying to lead them into danger, help them, or ask for help? Was there any sort of larger-scale weirdness going on at the same time?
(and feel free to mention anything else you think might be could be helpful)
Edited by Scorpion451Let me guess: It is about Rw By, specifically the illusion ppl speculated to be Neo's.
MAX POWER KILL JEEEEEEEEWWWWW

I know about the Master of Illusion trope, but I need a trope for illusions themselves. More specifically, there is no proof any master of illusion was around to make one, but there is 100% certainty an illusion happened.
For this example, the illusion was only there briefly, and also was able to vocalize.