Your Best Nightmare

This is all just a bad dream...
And you're NEVER waking up!

Flowey's message on the Game Over screen

Your Best Nightmare is the 79th track in the UNDERTALE Soundtrack. It plays during Omega Flowey's battle at the end of a Neutral Route.

The song is composed of various parts. The first part consists of a dark tune that samples the melody from You Idiot. This plays only at the start of his battle and is not included in the loop. A distorted version of Flowey's laugh plays before the song alternates between two parts: variations on the first tune with a breakcore beat during Flowey's fight and variations of Your Best Friend during the encounters with the SOULs. Flowey's segments are followed by the sound of TV static as a SOUL presents itself.

Trivia

• Unlike the other music files, mus_f_laugh, mus_f_noise, and mus_f_endnote are embedded in the game's data.win file rather than present as music files outside of it.
• A third section of this track, mus_f_part3, goes unused. Still, its "end note" and alarm appear separately as mus_f_endnote and mus_f_alarm.
• In the game, mus_f_saved plays after ACTing during the SOUL phases. This doesn't appear in the OST version.
• This is the fourth longest track in the Undertale Soundtrack after Bring It In, Guys!, Reunited, and Undertale.
• The drum loop in all parts of the song are heavily modified versions of Amen Break, specifically "squash" (which plays during the Flowey segments) and "cw_amen14_175" (which plays during the SOUL segments.)
• The lead instrument used in this track is the Freaky Choir pad from the Ultimate Sytrus Pack for FL Studio.
• The main parts using the "You Idiot" motif lack a clear tonal center, with the bassline being atonal and the melody being more obscure. The SOUL stages with the "Your Best Friend" motif are mostly modal, though the first is in plain E-flat major and the sixth and last is in D-sharp minor. Because of this, the track as a whole can be considered pantonal; not fixated on one tonal center and instead going through several arbitrary keys and modes, it has sections in A Locrian, which is highly unusual and irregular due to its diminished tonic.