The literary device where one object represents something else is called metaphor.

Here's a breakdown:

* Metaphor: A figure of speech that compares two unlike things without using words like "like" or "as". The comparison is implied.

Example:

* "The world is a stage." (Here, "the world" is being compared to a "stage", implying that life is a performance.)

Other examples:

* "Time is a thief."

* "Her heart is a stone."

* "He's a lion in the courtroom."

Note: While metaphors are a common literary device, it's important to distinguish them from similes, which use words like "like" or "as" to make the comparison explicit.