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From the intimidating Jaws theme to the creepy chorus noise of Squid Game, we explored why semitone intervals sound so sinister.

Semitone is the smallest interval used in Western classical music. As the name suggests, it is a half of a pitch, a "half step" or a small second.

Over the years, Western classical composers have used this tiny but powerful gap in their procedural music. Most notably, this interval appears in horror movies, and it is no more prominent than Steven Spielberg's 1975 classic movie "Jaws."

Read more: John Williams proves how terrible two repeated notes in this ominous soundtrack are

When Williams played the main two-note theme to Spielberg on the piano for the first time, the director initially smiled and thought it was a joke. Williams then supported his musical choice by describing the theme of playing on the tuba, "like a shark, instinctively, ruthlessly, and unstoppably worn to you." Fear!

"Jaws" is not the only famous example of the use of intervals in creepy film music.

Netflix's latest popular survival drama "Squid Game" is a music created by an artist, which is only called "23". He created one of the most well-known tunes in the show, Pink Soldier.

The creepy voice emphasized the pink soldiers, who appeared as a kind of law enforcement officer during the game.

This particular soundtrack is accompanied by some of the most creepy moments in the Squid game, when the faceless guards appear on the screen, the music is often played.

Whenever you play an unforgettable tune, you will know that something disturbing is about to happen, and the audio will put the audience on the edge of the seat.

Watch here: A cappella ensemble perfectly sings the "Squid Game" soundtrack will haunt your dreams

The vocal part alternately sings the minor third (A♭ to F) and minor second (A♭ to G). Both are relatively small intervals, so they have given the listener an uneasy feeling, but repeating these two intervals throughout the 30-second piece of music can create an elongated and disturbing listening experience.

Other famous examples of sinister semitone soundtracks can be found in the 1960 Alfred Hitchcock movie "The Cry" murder shower scene.

The terrible scene is accompanied by a collision of semitones, because D♯ and E are played at the same time. The result is a strong and disturbing emphasis on the scene of the bloody murder.

Read more: 13 scariest movie soundtracks of all time

However, works featuring semitones are not always creepy works themselves. A notable example is Für Elise's opening theme.

The first five notes of this piece are a minor second interval repetition, which is a theme that runs through the rest of the piano solo composition.

However, although you may not associate the Beethoven trivia of 1810 with all the creepy things, it is most likely because of the semitone content.

Listen to the beginning of "For Alice." The opening theme is resolved on the note of A, after teasing the fifth (E) and sharpening the fourth (D♯). When the piano falls in A major and the left hand joins, fixing us in A minor, there is almost a sense of relief.

Read more: When Will Smith played Beethoven on the piano in an impromptu scene, the actor was "silent"

Now imagine the opening of Für Elise, but this time, there is no solution. In fact, the whole piece is only the first four notes, E, D♯, E, D♯, repeating, repeating...

There is no denying that this choice of music is creepy (and boring). However, Beethoven started "To Alice" with this disturbing little two seconds, which resolved the anxiety-causing interval within a few seconds after introducing it, thus giving us a warm feeling.