Answer:
It happens when something has been cut with H2O.
When you stop and look, you can always see me. If you try to touch, you cannot feel me. I cannot move, but as you near me, I will move away from you.
I can travel from there to here by disappearing, and here to there by reappearing.
As I walked along the path I saw something with four fingers and one thumb, but it was not flesh, fish, bone or fowl.
What two things can always see what the other sees, but can never see each other?
Almost everyone needs it, asks for it, gives it. But almost nobody takes it.
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?