Answer:
There are millions of me. I am very small but when moving fast I am deadly.
I am round as a bowl, deep as a tub, but all the world's water couldn't fill me up.
Searing 'cross the pitch-black skies, I scream in celebration, Yet moments later, my outburst through, I am naught but imagination.
Sometimes I am loud. And viewed with distaste. Poke out my 'eye', then I'm on the front of your face.
My first is in blood and also in battle. My second is in acorn, oak, and apple. My third and fourth are both the same. In the center of sorrow and twice in refrain. My fifth starts eternity ending here. My last is the first of last, Oh Dear.
You use it between your head and your toes, the more it works the thinner it grows.
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?