This is an actual support ticket our help desk received this morning:
I can see and hear everyone in the class. They can hear me. They can not see me.
Wow! Philosophy classes have gotten a lot more intense this year!
(In fairness, this seems to pertain to video in an online class, but absent any formal acknowledgment of that in the ticket, I choose to believe this professor is a ghost.)
Absent any other information, the ticket does not say it’s a philosophy class. Could it be physics? (Which I recall from high school was called “philosophy” back then.) Perhaps an optics class? Maybe it’s British Literature, literally studying “The Invisible Man”? Chemistry — a solvents demonstration gone awry? Computer science compression algorithms taken once step to far?