Which literary device uses an implied comparison between unlike things?

The correct choice is indeed a metaphor, which is a literary device that creates an implied comparison between two unlike things without using "like" or "as." For instance, when one says, "Time is a thief," it suggests that time stealthily takes away moments and experiences from our lives, similar to how a thief would take belongings. This comparison conveys deeper meaning and emotional resonance, allowing the reader to perceive time in a more relatable or impactful way. Metaphors are powerful tools in literature because they can convey complex ideas in a more vivid and imaginative manner.

The other options represent different literary devices that do not fit the definition of an implied comparison in the same way. Allusion refers to a reference to another work of literature or a historical figure, which does not involve a comparison between unlike things. Analogy is a comparison that explains a concept by showing how two different things are similar, often using a more extensive explanation than a metaphor. Personification involves attributing human traits to non-human entities, which also does not create an implied comparison between two unlike things.