I've now seen two different deltarune theory videos that describe gaster's theme as having an interval of seven semitones and then pointing out other music that uses that same interval to assess how likely it is that it's a deliberate reference to gaster's theme but without at any point clarifying that an interval of seven semitones is more commonly known as a "perfect fifth" and is actually the second most universal interval in all of music after the octave and it's actually harder to find music that doesn't contain any perfect fifths than music that does
it's such an irresponsible writing decision you know. perfect fifths are one of the first things you learn about if you study music theory for any amount of time. referring to it by the width of the interval in half steps instead of by its more common name makes it sound more mysterious and special than it actually is. it's leading an audience who doesn't know anything about music theory except a vague understanding of the word "leitmotif" to think "yeah, why would both of these tracks have a melody with two consecutive notes separated by exactly seven semitones if one isn't meant to be a reference to the other?" even though that question has a really obvious answer that anyone who knows anything about music theory should be able to explain
calling perfect fifths a motif is like calling "uses words with the letter 'e' in them" a typing quirk
