MacGuffin

MacGuffin was created by Alfred Hitchcock it can be referred as a hidden catalyst which moves the plot on to create scene or ending with a twist. It can also be referred as the engine that sets the story in motion. It can be anything or nothing at all. In The 39 Steps, it is "secrets vital to your air defence"; in Number Seventeen it is a valuable piece of jewellery, while in The Lady Vanishes it is, in the most perfectly abstract of all Hitchcock's MacGuffins, a coded message contained in a piece of music. Examples of these are in the films such as:

The top secret plans in The 39 Steps (1935).
The eponymous statuette in The Maltese Falcon (1941)
The letters of transit in Casablanca (1942)
The uranium in Notorious (1946)
The case with glowing contents in Kiss Me Deadly (1955)
The "government secrets" in North by Northwest (1959)
The stolen $40,000 in Psycho (1960).
The stamps in Charade (1963)
The Death Star plans in Star Wars Episode IV: A New Hope (1977)

Many people may pre-vay this media concept as a cliff hanger shot used by cameramen, but in actual words it is something that creates meaning for the nest scene.