Answer:
What is it that no man ever saw, which never was, but always will be?
What is something yet nothing, but if you fill it up it will disappear?
Which popular cheese is made backwards?
What has 4 fingers and a thumb, but is not living?
Other terms for this handy device include doohicky, doo-dad, and whatchyamacallit.
It is something you will never see again.
Easy
Animal
Difficult
Food
Funny
Kids
Logic
What am I?