Which figure of speech is used in this text?
Everything in this room is eatable, even I'm eatable! But that is called cannibalism, my dear children, and is in fact frowned upon in most societies.
—Willy Wonka in Charlie and the Chocolate Factory

 - understatement
 - apostrophe
The text uses understatement, which involves deliberately representing something as less serious or important than it really is.
Frowned upon in most societies is an understatement, since cannibalism—the eating of human flesh by another human being—is usually looked upon with horror.