In Invincible (The Flash 2014 S02E22), Caitlin hallucinates Zoom appearing in front of her. I think it is a hallucination, but I wonder: Can a speedster move fast enough that they can remain unnoticed by everyone in a room, except select people?
I see several problems:
- The crackling/sparks from Speed Force lightning
Of course, it's the speed of the speedster that should cause the invisibility, not the conditions in the room. The Flash crouching in a corner behind a flower pot in a poorly-lit auditorium with just a janitor sweeping the floor doesn't count.
I don't think the Flash in the current TV show has shown this ability (or any other speedster in that show), or that anybody in that show has enough control over air and the Speed Force discharges to be able to do so. If one has, it would be great, but if not, an example from any of the DC speedsters would do.