Answer:
It is something you will never see again.
Born in the past, but only lives in the present. Sometimes false, always personal.
Mary's child slept in one of these
What goes trough your head but you forget it like 3 days after?
What instrument can make any sound and be heard but not touched or seen?
All about, but cannot be seen, Can be captured, cannot be held, No throat, but can be heard. Who am I?