By Toby Fox tobyfox Bandcamp tobyfox Twitter toby.fangamer.com Other fwugradiation Tumblr ← Game Main Theme (Piano Sketch) Previous track by this artist → King Boss (Orchestral) Next track by this artist.
Duration: 0:17.

Listen on YouTube or undertale.wiki.

Read wiki commentary.

Tracks that reference Gaster's Theme:

from Fandom:

• Spoopy Piano o-o; by bobthetacocat
• Gaster's Theme by Cristata

from Beyond:

• 🕆︎☠︎☼︎☜︎💧︎🏱︎⚐︎☠︎💧︎✋︎✞︎☜︎📪︎ ☼︎☜︎👎︎✌︎👍︎❄︎☜︎👎︎ by hywell and Cristata
• ANOTHER HIM by Toby Fox
• CORE [BRUTALIZED] by Jebb
• bangin sermon man by MacK
• UNALTERED by tsundereCat [TC]
• KNIGHTMARE'S NIGHT by Torrent 64
• [S] Alterior Motif-ment by Erik Scheele
• All The World's a Cage! by ruby
• Flashback Remix by Hart
• Twilight Reverie ~ Penumbra Phantasm by Torrent 64 and Tee-vee
• An Ordeal of the Dreaming by ruby

Wiki commentary for Gaster's Theme:

8/24/2025 Quasar Nebula: wiki editor

Not released on any soundtrack album. This track name is from the in-game sound test room; in the game files it's mus_st_him.ogg.