hold on just a fucking second.
This… this can’t…..
NO.

Here is a map of (almost) every song on the OST used in the game, and which ones share similar compositions or can lead into one another.

The whole of Undertale’s soundtrack has 22 leitmotifs iirc, each centered around a character or theme, and some overlapping.

Basically the entirety of Undertale’s soundtrack itself contains spoilers, foreshadowing, and secrets that all link together in some form or another.