phantom

nouns

a ghostly appearing figure
"we were unprepared for the apparition that confronted us"
something existing in perception only
"a ghostly apparition at midnight"

adjectives

something apparently sensed but having no physical reality
"seemed to hear faint phantom bells"; "the amputee's illusion of a phantom limb"
is similar to
not actually such; being or seeming fanciful or imaginary
"this conversation is getting more and more unreal"; "the fantastically unreal world of government bureaucracy"; "the unreal world of advertising art"