Undertale Music Discs 1.18.1.zip is a release file of the Minecraft resource pack Undertale Music Discs, made for Minecraft 1.16-Snapshot, 1.17.1, 1.9.1, 1.16.3, 1.13.1, 1.9.3, 1.8.7, 1.15-Snapshot, 1.16.1, 1.18.1, 1.10-Snapshot, 1.9.4 and more. It was published on December 14, 2021 and is 14 MB in size. For the full description, screenshots and every other version, visit the Undertale Music Discs resource pack page.
How to install: Put the .zip into .minecraft/resourcepacks (do not extract it) and enable it under Options → Resource Packs.