Guess Me!

What Am I?

Small, (sometimes huge) dark brown, and crunchy when you stomp on me.

I'm more afraid of you than you are of me.

I crawl around minding my own business, and just out of no where I find myself running from a big black thing with grews.

I run for my life, literally.

Humans hate me.

I look scary, but I wouldn't dare harm them.

So tell me what am I?