Which literary device involves extreme exaggeration for emphasis?

Hyperbole is indeed the literary device that involves extreme exaggeration for emphasis. It is used to create a strong impression and to evoke strong feelings or laughter. For instance, someone might say, "I'm so hungry I could eat a horse," not to suggest they would literally consume such a large animal, but to emphasize their very strong feeling of hunger.

This device serves various purposes in literature and everyday language, such as to enhance the dramatic effect, to stress a point, or to infuse humor into a statement. By using hyperbole, writers can capture the attention of their audience and make their descriptions more vivid and relatable.

Metaphor, while also a strong literary device, compares two unlike things directly but does not imply exaggeration. Similarly, simile employs comparison using "like" or "as" and suggests likeness rather than exaggeration. Personification attributes human characteristics to non-human entities, which is a distinct function from the amplification that hyperbole provides.