The answer is allegory, since allegory is a rhetorical device that convey hidden meanings through symbolic figures in a literary piece which create the meaning the author wants to portray. It is in a form of story or poem and the meaning could be political or moral, depending on the author's true meaning.
There is no plot. Can you please add a picture.
This could be the death of a family member, or a certain academic/athletic achievement. Maybe the day you got a pet or the day that pet died. Maybe when you completed an important goal. If it's an important memory to you, you could use it.
