The extensive use of leitmotifs in Undertale's soundtrack and other sound files helps create a nostalgic mood for the game and often evokes emotional responses in players. Toby Fox has stated that the majority of Undertale's soundtrack was composed using reiterations of free Soundfonts and synths.
Attempts have been made at documenting all of the leitmotifs used in the game; players frequently find new connections, and it may be impossible to list them all conclusively. Every single piece of data is open to interpretation and any change should be explained in this page's history description.
Timestamps found below are approximate to one second and are sourced from this playlist, which reflects the timing of the official soundtrack.
Once Upon a Time
This leitmotif can be considered as the main theme of Undertale. It is the most common melody of the game, playing in seventeen tracks.
- Once Upon a Time
- Start Menu and Menu (Full) (the background tracks for the Start Menu build upon one another, with five intermediate tracks in between; the music played in the menu after completing the True Pacifist Route is a slowed rendition of Start Menu)
- Home and Home (Music Box) 0:36–1:44
- Hotel 0:20–1:22
- Can You Really Call This A Hotel, I Didn't Receive A Mint On My Pillow Or Anything 0:14–0:57
- Undertale 0:37–4:41, 5:20–5:58
- The Choice
- Fallen Down (Reprise) 1:18–2:30 syncopated to 3/4
- Hopes and Dreams 0:00–1:29, 1:52–2:14
- SAVE the World 0:00–0:14, 0:35–1:46
- Final Power (Hopes and Dreams reversed)
- Reunited 0:43–3:56
- Bring It In, Guys! 3:47–4:05
- Last Goodbye 0:00–0:25, 0:45–2:15
- Good Night
- Undertale (Unused)
- Before the Story 0:29–1:28
Flowey has two leitmotifs relating to him.
Your Best Friend
This leitmotif occurs in seven songs, and one unused audio file.
- Your Best Friend
- Your Best Nightmare 0:54–1:26, 2:00–2:27, 3:00–3:27
- Finale 0:00–0:40, 0:57–1:52
- Hopes and Dreams 1:18–1:52
- SAVE the World 0:05–0:08, 0:15–0:18, 0:25–0:28, 0:36–0:39, 1:35–1:46
- Last Goodbye 0:29–0:32, 0:39–0:42
mus_toomuch (this song plays after exhausting the random kill counter of an area)
Your Best Nightmare
This leitmotif is used in three songs.
- You Idiot
- Your Best Nightmare 0:00–0:16, 0:22–0:53, 1:27–1:54, 2:29–2:54, 3:28–4:00
- Burn in Despair!
- Fallen Down (the track in-game is played 25 cents above C# major in A440 equal-tempered tuning; the sheet music shown above is written in D major)
- Fallen Down (Reprise) 0:00–1:18
- Bring It In, Guys! 3:34–3:47 syncopated to 4/4
- Empty House (a slower version of Fallen Down)
- Waterfall 0:27–1:56
- Quiet Water
- NGAHHH!! 0:34–1:22
- Spear of Justice 0:36–1:55
- An Ending, has a variation of the melody
- Don't Give Up, uses variation
- Respite, uses variation
- But the Earth Refused to Die, uses variation
- Bring It In, Guys! 1:48–2:14, uses variation
- Battle Against a True Hero 0:44–1:35, uses variation
mus_ruinspiano(variation of An Ending)
- Undyne Battle (Unused) 0:29–1:17
This leitmotif is related to enemies or dogs. It appears in nine songs and one unused song.
- Enemy Approaching
- Anticipation (bassline) (this song also plays at extremely reduced speeds when battling Monster Kid, during the final encounters with Flowey in New Home on the Genocide Route, and at the end of a "Soulless" Pacifist playthrough)
- Heartache 0:53–1:03
- Dogsong, has the variation of the melody (a slowed-down version of this song plays after meeting Endogeny's sparing conditions)
- Temmie Village, also has the variation
- Tem Shop, also has the variation
- Stronger Monsters
- Bring It In, Guys! 0:00–0:34
- Donation Shrine (Boombox)
This leitmotif is used in five songs. Most of which are the boss themes of various mini bosses.
- It's Raining Somewhere Else (this song is played slightly slower in Sans's Room)
- Song That Might Play When You Fight Sans
- Bring It In, Guys! 0:40–0:46
- Nyeh Heh Heh!
- Bonetrousle (this song is played at an extremely reduced speed when encountering Papyrus for the last time in the Genocide Route)
- Song That Might Play When You Fight Sans 0:33–0:58
- Bring It In, Guys! 0:34–0:53
These leitmotifs have two separate meanings to them.
- Snowy (a version of this song plays when fighting Snowdrake's Mother. It is heavily distorted, changing pitch and speed randomly every few seconds)
- Snowdin Town 0:00–0:56
- Shop 0:00–0:25
- Dating Start! 0:00–0:16, 0:37–0:54, 1:31–1:56
- Dating Fight! 0:00–0:13
- Bring It In, Guys! 0:54–1:16
Used to represent friendship, love or happiness. Used in eight songs.
- Snowdin Town 0:56–1:16
- Shop 0:25–0:50
- Dating Start! 0:16–0:35, 0:54–1:31
- Dating Fight! 0:13–0:35
- Hopes and Dreams 2:15–3:01
- Reunited 3:56–4:25
- Bring It In, Guys! 1:16–1:29
- Run! syncopated to 4/4
- Dating Tense! 0:17–0:25 syncopated to 4/4
- NGAHHH!! 0:00–0:34, has the variation of the melody
- Spear of Justice 0:00–0:36, also has the variation
- ASGORE 2:28–2:36, syncopated to 4/4, also has the variation
- Bring It In, Guys! 1:29–1:48, also has the variation
- Undyne Battle (Unused) 0:00–0:29, 1:17–1:30 has the variation of the melody
- Waterfall 0:00–0:27, 1:56–2:07
- Another Medium 0:00–0:51, 0:59–1:21, 1:51–2:10
- CORE has a variation of the melody.
- Death by Glamour, also has variations.
- Bring It In, Guys! also has variations (including the one from Death by Glamour.)
- Bird That Carries You Over A Disproportionately Small Gap
- She's Playing Piano
- Here We Are syncopated to 5/4
- Alphys Lab (Unused) also syncopated to 5/4
Mettaton's main theme. Found in four songs and at least one other sound file.
- Metal Crusher 0:03-0:20 with variations and changes in note values without syncopation
- It's Showtime!
- Live Report syncopated to 3/4
- Death Report syncopated to 3/4
- Death by Glamour 1:30–1:56
mus_tv(i.e., Papyrus's TV)
The bassline of It's Showtime! is present in three Mettaton-related songs. It is considered as a separate leitmotif, as it has an entirely different melody.
- It's Showtime! (bassline)
- Can You Really Call This A Hotel, I Didn't Receive A Mint On My Pillow Or Anything
- CORE Approach
Asgore is related to two leitmotifs. Both are used in his fight theme.
This motif is used in two songs, one unlisted song and an unused audio file.
- Determination (as Photoshop Flowey laughs at the protagonist for dying to him, this song is sped up, looped, and played over itself)
- ASGORE 1:50–2:28 syncopated to 4/4
This motif is used in three songs.
- Undertale 0:00–2:47, 3:27–6:21 (at times, the melody is barely perceptible among overlapping music. It is heard on a guitar for most of the song, becoming hard to distinguish after 3:27; the tune switches to a more audible sample after 4:42, to a quiet background piano at the key change around 5:20, and back to the second SoundFont at 5:57)
- The Choice (imperceptible, as it is a slowed-down part of Undertale which contains the barely-audible Memory)
- Finale 0:40–0:57
- His Theme
- The Joystick Config songs—Uwa!! So Temperate♫, ...Holiday♫, and ...HEATS!!♫—are all variations of each other.
- Home to Home (Music Box).
- Heartache to ASGORE 0:34–1:49.
- Dating Start! to Dating Fight!.
- Spooktune to Spookwave.
- Ruins 0:17-0:19 to Waterfall 1:12-1:17 to Spear of Justice 0:48-0:58 and 1:10-1:20, and Battle Against a True Hero from 1:35.
- Ghouliday to Jingle Bells.
- Live Report to Death Report.
- CORE 0:34–1:29 to Another Medium 0:52–2:22 and part 5 of Bring It In, Guys! 2:45–3:08
- The basslines of Death by Glamour 0:00–1:05 and Bring It In, Guys! 0:00–0:28 have the same melody, which is a variation of the CORE 0:00–1:01 bassline.
- Oh! One True Love to Oh! Dungeon and For The Fans.
- Battle Against a True Hero 0:00–1:36 to Power of "NEO".
- grandpatemi to Metal Crusher (introduction)
mus_dogroomto the PlayStation theme of the Dog Shrine.
- Gaster's Theme has debatable uses in some songs.
- snd_mysterygo is Gaster's Theme sped up and reversed.
- Sample used in Barrier is used in Amalgam
- Sample used in Ooo is used in Waterfall (0:14–0:25)
- A version of Flowey's laugh is used in Your Best Nightmare (0:16–0:22)
mus_smileis Muffet's laugh, slowed down and looped, with the audio being reversed every other loop.
- Sample used in Metal Crusher (0:00–0:04 and background) is used in Death by Glamour (0:39–0:58 and 2:02-2:14)
- Multiple songs from the soundtrack use instrument samples from other games.
- most of undertale's music was made using free soundfonts + synths but everyone likes it. that's cool - @FwugRadiation on Twitter, September 19, 2015. Archived on November 29, 2015.
- (Undertale) Once Upon a Time Leitmotifs - YouTube
- Undertale Main Menu Music Easter Egg - YouTube
- I heard that if you sped up “The Choice” (the music that plays when Sans is giving you Judgement) by 666%, you get “Undertale”. - bibliophilea on Tumblr, November 22, 2015.
- [Version 2] Undertale - All songs with the "Your Best Friend" melody/leitmotif - YouTube
- Undertale OST "But Nobody Came" Sped up 1200% - YouTube
- Undertale - All Songs With the "Your Best Nightmare/You Idiot" Leitmotif - YouTube
- Undertale - All songs with the "Fallen Down" melody/leitmotif - YouTube
- [Version 2]Undertale - All songs with the "Ruins" melody/leitmotif - YouTube
- [Version 2] Undertale - All songs with the "Enemy Approaching" melody/leitmotif - YouTube
- [Version 2] Undertale - All songs with the "Enemy Approaching" melody/leitmotif - YouTube
- it's all connected - YouTube
- Undertale - All songs with the "Ghost Fight" melody/leitmotif - YouTube
- Undertale - All songs with the "sans." melody/leitmotif - YouTube
- Undertale - All songs with the "Bonetrousle" melody/leitmotif - YouTube
- Undertale OST - Bonetrousle (GENOCIDE) Extended - YouTube
- Undertale - All songs with the "Snowy" melody/leitmotif - YouTube
- Undertale - All songs with the "Snowdin Town" melody/leitmotif - YouTube
- Undertale - All songs with the "Spear of Justice" melody/leitmotif - YouTube
- Possible Leitmotif? - YouTube
- Undertale - All songs with the "Waterfall / Overworld" leitmotif/theme ✔️ - YouTube
- See Patient
- Undertale - All songs with the "Alphys" melody/leitmotif - YouTube
- Undertale - All songs with the "It's Showtime!" melody/leitmotif - YouTube
- b5b7776b-681a-4a33-ba44-e5a8e6851814 - Image
- Undertale - All Songs With The "Metal Crusher" Leitmotif/Melody - YouTube
- Cucumber Quest - Noisemaster Theme - YouTube
- Undertale - All songs with the "Determination" melody/leitmotif - YouTube
- Undertale - All songs with the "ASGORE" melody/leitmotif - YouTube
- Undertale - All songs with the "His Theme" melody/leitmotif - YouTube
- Music similarities 2: Undertale: Finale and His theme - YouTube
- An Examination of Leitmotifs and Their Use to Shape Narrative in UNDERTALE – Part 2 of 2 - jasonyu.me
- Nearly UNKNOWN Gaster's Theme secret in Undertale (snd_mysterygo) - YouTube
- Undertale 'Barrier' sped up - YouTube
- W. D. GASTER "Mus_Smile" Dissected! - YouTube