Which figure of speech is used in this text?
I was helpless. I did not know what in the world to do. I was quaking from head to foot, and I could have hung my hat on my eyes, they stuck out so far.
—Mark Twain, Old Times on the Mississippi

 - hyperbole
 - euphemism
The text uses hyperbole, an obvious exaggeration that is not meant to be taken literally.
Could have hung my hat on my eyes, they stuck out so far is an exaggeration, since the speaker probably could not have literally hung his hat on his eyes.