Fairday's Riddles: Beep and Bop...

Hello, Riddlers! Can you guess the answer? Some of my favorite characters have these. ~ F

They honk to go or run to crash- signaling a mad dash. A horse with one isn't seen. When one is full, you'll not be lean. 

What am I referring to? Stop by Sunday for the answer

I gave you a clue!

FEAR NOT THE UNEXPECTED