
UNDERTALE WORLD
This is a dimensional exploration mod for Undertale. Although my personal technical skills are limited, I strive to recreate and expand the world of Undertale in Minecraft in my own way.
Screenshots




About this Mod

(Mcreator production)
this is a dimensional exploration mod for Undertale. Although my personal technical skills are limited, I strive to recreate and expand the world of Undertale in Minecraft in my own way.
Find a small hill in the Overworld. You need to use a Magic Stone — crafted from diamonds, bottles o' enchanting, and three emeralds — to activate the bedrock portal hidden inside the hill, which will take you to a mysterious Underground world.
Version 0.1 is very rudimentary, yet it already features two new biomes, a full set of new equipment, several new materials, four new generated structures, and a boss worthy of your challenge — Undyne — waiting for you to discover.
This is a mod made in China, and I will keep working hard to update it continuously.
The mod will be open-sourced on GitHub in the future.
Hereby declared: Part of the code is AI-assisted.
Although there are some limitations, I have decided to continue developing on MCreator. I will combine it with IntelliJ IDEA and try my best to complete the 1.0 official release (waterfall area complete and snowy plains test).
Available Versions
How to Install UNDERTALE WORLD on Your Server
Order Server
Order a Minecraft Java server with at least 4 GB RAM (6 GB recommended).
Set neoforge Loader
In the panel under "Egg", select the neoforge loader and matching Minecraft version (1.21.1).
Install Mod
Open the mod browser in the dashboard and search for "UNDERTALE WORLD". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.
Compatibility
Mod Loaders
Minecraft Versions
1.21.1
Server-side
✓ RequiredRecommended RAM
6 GB(min. 4 GB)Frequently Asked Questions
UNDERTALE WORLD server crashes on startup – what to do?
Most common cause: wrong neoforge version or insufficient RAM. Check the server log (latest.log) for "OutOfMemoryError" or "Mixin" errors. With Mado Hosting: ensure at least 4 GB RAM is allocated and the loader matches the mod version (1.21.1). You can switch loaders with one click in the panel.
Is UNDERTALE WORLD compatible with neoforge?
UNDERTALE WORLD officially supports neoforge for Minecraft 1.21.1. The Mado dashboard automatically detects incompatible loader combinations.
Server lagging with UNDERTALE WORLD – how to optimize performance?
Recommended RAM: 6 GB (per 5 players). Use /spark profiler to check if UNDERTALE WORLD consumes the most tick time. Common fixes: reduce server view-distance to 8-10, install "performant" or "starlight" as supplementary mods on Forge. With Mado Hosting, your server runs on NVMe SSDs with dedicated CPU cores for minimal latency.
Similar Mods
Rent Modded Server
Install UNDERTALE WORLD with just one click on your server.