Answer:
You use it between your head and your toes, the more it works the thinner it grows.
My first is an insect; my second is a border; my whole puts the face in a tuneful disorder.
It is a part of us, and then replaced. It escapes out bodies, to a better place. The world becomes its sizeable home. Its passions unrestraint, the planet it roams.
When I’m metal or wood, I help you get home. When I’m flesh and I’m blood, In the darkness I roam.
Hold the tail, while I fish for you.
It's what light turns into in the night
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?