disappear, etc. into thin air
disappear into thin air
To vanish completely and without a trace. I would give you my stapler, but it seems to have disappeared into thin air.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
disappear, etc. into thin ˈairdisappear, etc. suddenly and in a mysterious way: The money vanished into thin air. Nobody knows what happened to it.
Farlex Partner Idioms Dictionary © Farlex 2017