The wind.
air
It never came out.
jamais vu is spelled 'never seen' in English.
Nunca te he vista antes.
Jamais vu in French means "never seen (before)" in English.
nobody knows, because that "creature" has never been seen. with proof to show that it was seen.
air
nobody has been seen on Pluto because Pluto might not be a planet
His grandfather has never been named (as far as I can find) & is apparently still alive, but never seen.
Tomorrow
Nothing. The flow of time will never reach infinity. Therefore, even if humans and the universe can exist for infinity years, nobody will still know what happens then because this time will never be seen
Because nobody has found them or seen them yet
He has never been seen
Unicorns have never been seen. They are not real and never have been.
She has never been seen. She is a myth.
you
nobody knows how Hudson died. his crew put him on a ship and was never seen again