Question

The Misfit's assertion that he was "buried alive" is an example of _____.

Answer 1

I think the answer is a hyperbole to show how awful his life in prison was for him

Answer 2

Metaphor

As you may know after reading the story, of course the misfit was not buried alive.  What this phrase is taken from is a portion of the tale where he is recanting his experience and in an effort to paint a picture of just how horrible his time was in the penitentiary.  He uses a metaphor by comparing his time there to being buried alive.  One thing to keep in mind as you read and analyze future works of literature is that any time comparisons are being made that are not technically/literally true, it’s a safe bet what you’ll have on your hands is figurative language—a metaphor.