Answer:
Hoofed frolicking.
I can be written, I can be spoken, I can be exposed, I can be broken.
There are millions of me. I am very small but when moving fast I am deadly.
Who makes it, has no need of it. Who buys it, has no use for it. Who uses it can neither see nor feel it. What is it?
My tongue hangs out as I run over fields and streets all day. I get tied up every morning and untied at night.
When is it bad luck to see a black cat?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?