1. Foreshadowing

2. Foreshadowing
The simplest form of foreshadowing is by mentioning something that will be later used in the story. Usually, it is mentioned in passing or described as part of a set of seemingly unimportant things. The best example is that of Chekhov's gun: when a certain setting is described, it is mentioned that a loaded gun is hanging on a wall. Much later on, this gun is taken off the wall and fired.
To draw the reader's attention to the otherwise subtle foreshadowing element, writers may often make repeated references to the object throughout the story.
Source: wikipedia