Undermod
ModSewers that link villages together, giant craters, underground forests, rivers and seas.
Why gradeC
How grades workStrengths
Points lost
- No release in 18 months−8 points
- No source code link−7 points
- Releases in only 3 of the last 24 months−4 points
- Many modpacks removed it−4 points
All 11 criteria
Maintenance
9 points lost18 / 27Last releaseHow long ago the newest file came out, or an existing file was marked as working on a new Minecraft version.18 months ago (23 Apr 2025). 94 modpacks released in the last 6 months still include it, so it keeps 58% of these points. 7 / 12Supports popular versionsWhether the project has a file for a Minecraft version that 15% or more of the popular mods updated in the last 6 months also support. A version many modpacks use, like 1.20.1 or 1.21.1, also counts after a release in the last 12 months.1.20.1 on Forge. 77% of the 516 popular Forge mods updated in the last 6 months also have files for 1.20.1. Latest Minecraft: 26.3. 9 / 9Regular releasesIn how many of the last 24 months a new file came out. Full points at 8 months.Releases in 3 of the last 24 months 2 / 6Stability
4 points lost18 / 22Removed from modpacksHow many modpacks removed it in a later version of the pack. We can only see this in modpacks with two or more versions. A pack that swaps it for another edition of the same project, or that is rebuilt from scratch, does not count.48 of the 227 modpacks with two or more versions removed it in a later one (21%) See the 48 modpacks6 / 10Quick fixesHow often a release needed a quick fix: a new release within 3 days to fix a problem in it.1 of its 7 releases in 2 years needed a quick fix (14%) 7 / 7Known conflictsHow many projects say they do not work with it, compared with how widely it is used. Packs, small projects, forks, ports, add-ons, alternatives and old versions do not count.None 5 / 5Transparency
7 points lost3 / 10Source codeWhether the project page links to its source code, so anyone can read what it does.No link on the project page 0 / 7Place to report problemsWhether the project page links to a place where players can report problems: an issue tracker.issues.undermod.net 3 / 3Popularity
Full points4 / 4DownloadsDownloads on Modrinth and CurseForge. Full points from 5 million.1,045,430 4 / 4Track record
3 points lost5 / 8AgeHow long the project has existed. It counts less when no new file came out recently.20 months, 6 releases 5 / 8Security
PassedFile checksThis check adds no points. It can only take points away.Our checks found nothing harmful in the latest file for recent Minecraft versions. See Security
47.8 of the 71 points that apply = 67 out of 100. The points above are rounded to whole numbers.
Images
About
Undermod expands Minecraft exploration with procedural underground biomes and landforms that connect into a broader network beneath the Overworld, while adapting generation to existing worlds and working alongside most world-generation mods. Ancient sewers can run beneath villages and link them through flooded tunnels, draining into underground rivers or seas; their abandoned chambers may house bandits and other outcasts, while mushrooms, spiders, rats, slimes, and dangerous leeches inhabit the damp passages. Underground forests grow beneath surface woodlands, where sinkholes admit sunlight to trees and plants, and can connect with caves, chasms, mineshafts, rivers, and sewers; they are rich in coal and may also contain lapis lazuli, diamonds, or glowstone. Rare impact craters expose caves, chasms, and mineshafts, with meteorite remains at their centers, and may become grassy and wooded, water-filled, or barren depending on their location. Underground rivers offer boat routes between distant points and connect cave systems, sometimes flowing into subterranean seas that range from lake-sized waters to vast underground horizons with fish, leeches, and drowned zombies. The mod also generates uncommon caverns of varied sizes, often marked by stalactites and sometimes breaking through to the surface. Exploration is supported by clues and maps: cartographers may sell sewer maps, bandits can hide them in underground forests, and old sewer maps can point to craters or subterranean seas. New finds include Heaps of Filth, which slowly attract leeches in water or slimes on land when placed in murky biomes, can be cleared to stop those creatures returning, and may conceal valuables. Understeel, mined in ancient sewers, provides grated fences, doors, and redstone-operated trapdoors for open barriers, railings, and builds. Black Veil Mushrooms can be cultivated in very dark conditions as a brewing alternative to Nether Wart.
Written from Modrinth and CurseForge . How we write it
In-game changes
Changes the game's code in 4 areas: Chunk loading and storageChanges 1 game code file in this area: how the game loads, tracks, saves and unloads chunks., World generationChanges 1 game code file in this area: terrain, biomes and structures made when new land is created., Rendering and graphicsChanges 1 game code file in this area: drawing mobs, items, particles and textures on screen. and PlayerChanges 1 game code file in this area: your character: movement, abilities, hunger and controls..
Adds 31 blocks, 12 items, 1 mob, 1 other entity, 1 enchantment, 14 recipes, 1 loot table, 12 sounds and 3 key bindings.
Counted from the names and data files in the mod, so the list may not be complete.
Keeps all of vanilla Minecraft's textures, models and sounds.
Often used with it
See all 30Details
- Creator
- Mystronics
- License
- All rights reserved
- Downloads
- 1M
- Created
- 21 Feb 2025
- Official pages
- Modrinth , CurseForge
Security
No harmful code found
We checked its files and read their code, without running it.
What it can do on your computer
- Creates settings files
- The mod keeps its settings in the config folder of your game, where you can change or delete them.
Why we show this: a mod runs on your computer like any program, so harmful code in it can take your accounts or files. Our checks look for known signs of harm. They cannot prove that a file is harmless. In the grade: malware means no grade, and a Warning in a latest file for a recent Minecraft version lowers it.
How we checked
- FilesWe download the files from Modrinth or CurseForge and look at what is inside them and what their code can do, without running them. Fixed rules tell what is harmful.3 latest files: the newest file for each Minecraft version and loader. The answer above is about the one for a recent version. Recent versions: those released in the last 2 years, plus 1.20.1 and 1.21.1, among the most played in modpacks. See each file in Releases
- Their codeWe turn the code of the files back into readable code and follow what it does, without running it. This shows what it downloads, what it sends and where your login goes.Read without running it
- Author on ModrinthThe disclosure form on Modrinth, where the author declares that the project reads or edits things on your system outside the game. Since 13 Aug 2026, Modrinth's rules require it when this applies.Nothing declared about your system outside the game.
- Looked for, not foundWe looked for these in the file and did not find them.The internet, folders outside the game, other programs, updating itself, the webcam or microphone, an AI service.
Privacy
We found nothing it sends
We read its code without running it: it contacts no web address while you play.
Why we show this: a mod can send things about you over the internet, like your player name or your login. Contacting an address to check for updates or download files sends nothing about you. Not in the grade: sending data can be normal for what a mod does.
How we checked
- Files readWe read the code without running it. We list each web address the code contacts while you play, and what it sends. Code that is never used is left out.The code of its one file, for recent Minecraft versions. See each file in Releases
- Author on ModrinthThe disclosure form on Modrinth, where the author declares crash reports, usage data and advertisements. Since 13 Aug 2026, Modrinth's rules require it when a project collects data on its users or shows advertisements.Nothing declared about crash reports, usage data or advertisements.
AI
No sign that AI was used to make it
We looked for AI tools in its texts, files, images and sounds and found none.
No sign of AI in the game
We found no AI service, AI library or AI model file in its code.
Why we show this: some players and servers avoid projects made with AI, and AI in the game can send what you write to an online service. Not in the grade: using AI does not tell whether a project works well or is kept up to date.
How we checked
- Author on ModrinthThe disclosure form on Modrinth. Since 13 Aug 2026, Modrinth's rules require it when a substantial part of the code is AI output, when an asset is mainly AI output, or when the project or its page relies on generative AI.No AI content or AI features declared.
- Description and changelogsThe description, project page and newest changelogs: sentences saying an AI tool was used, and text pasted from an AI chat.Nothing found13 changelogs read
- Its filesFiles that AI coding tools leave behind (like AGENTS.md), and the texts inside the files you download.Nothing found
- Images in its filesHidden data in the images of the files you download, where AI image tools write their name and settings.Nothing found35 images read
- Sounds in its filesThe tags of the sound files in the files you download, where some AI music tools write their name.Nothing found39 sounds read
- Code of the modThe code and files of the mod, read without running it: addresses of AI services, AI libraries, AI model files and a place for your own AI key.No AI service, AI library or AI model file577 code files read
Compatibility
See all 6 filesPoint at or tap a version to see its loaders.
Modpacks using this project
Find modpacks with it| Oct 2024 | 0 |
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| Nov 2024 | 0 |
| Dec 2024 | 0 |
| Jan 2025 | 0 |
| Feb 2025 | 0 |
| Mar 2025 | 0 |
| Apr 2025 | 15 |
| May 2025 | 21 |
| Jun 2025 | 24 |
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| Oct 2025 | 27 |
| Nov 2025 | 32 |
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| Jan 2026 | 33 |
| Feb 2026 | 28 |
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| Apr 2026 | 30 |
| May 2026 | 24 |
| Jun 2026 | 16 |
| Jul 2026 | 23 |
| Aug 2026 | 25 |
| Sep 2026 | 20 |
292 modpacks include Undermod in at least one of their versions. Here are the 30 most downloaded.
Biohazard: Project Genesis - The Ultimate Apocalypse965K downloadslast version with it 13 Sep 2026
Beyond Cosmo525K downloadslast version with it 28 Nov 2025
SUPERIOR - RPG513K downloadslast version with it 10 Jul 2025
The Last War - Guns And Adventure312K downloadslast version with it 19 Oct 2026
ChaosZProject - A Modern Zombie Apocalypse [VR for WIP v.3.0.0]213K downloadslast version with it 8 Jun 2025
PandAce's World101K downloadslast version with it 18 Nov 2025
Protocol Zero - A Modern Zombie Apocalypse 101K downloadslast version with it 15 Jun 2026
Gun n craft63K downloadslast version with it 19 Apr 2026
Record of Wonderland47K downloadslast version with it 10 Oct 2026
Cataclysm Zombie Apocalypse33K downloadslast version with it 12 May 2026Often in the same modpacks
Mods that modpacks often add together with Undermod. Share: how many of the modpacks with Undermod also have that mod.
AmendmentsAModin 54% of the modpacks with Undermod
BlueprintAModin 53% of the modpacks with Undermod
YUNG's Better Nether FortressesAModin 51% of the modpacks with Undermod
Sodium Dynamic LightsCModin 50% of the modpacks with Undermod
YUNG's Better Ocean MonumentsAModin 50% of the modpacks with Undermod
AttributeFixAModin 49% of the modpacks with Undermod
YUNG's Better Jungle TemplesAModin 46% of the modpacks with Undermod
YUNG's Better End IslandAModin 46% of the modpacks with Undermod
Alex's CavesCModin 45% of the modpacks with Undermod
Serene SeasonsAModin 42% of the modpacks with UndermodLatest files
The newest file for each Minecraft version and loader. The files for recent versions come first. Recent versions: those released in the last 2 years, plus 1.20.1 and 1.21.1, among the most played in modpacks.
6 releases
Quick fixes
In the last 2 years, 1 release needed a quick fix: a new release within 3 days to fix a problem. This counts in the grade, but it is too few to lose points.
See them, newest first
Quick fixesReleases followed within 3 days by a new release that fixes a problem in them.1
- Undermod-1.16.5-0.1.2r.jar…with other world generation mods. Fixed indeterministic generation error. Increased…