Install Mutant Monsters on Minecraft

Mutant Monsters adds oversized, stronger versions of familiar mobs, including a Mutant Zombie, Skeleton, Creeper, Enderman and Snow Golem, plus the weapons and armour you earn from beating them. It has to be installed on the server and in every player's game. It runs on NeoForge and Fabric for current Minecraft versions.

Checked against Mutant Monsters 26.3.1 on NeoForge with Minecraft 26.3, October 2026.

What it needs

Mutant Monsters is a mod, not a plugin, so Paper and Purpur servers can't load it. The 26.3.1 release comes in two builds:

• NeoForge: requires Puzzles Lib.
• Fabric: requires Puzzles Lib, Fabric API and Forge Config API Port.

Minecraft 26.x runs on Java 25, which the panel picks for you. Forge builds stop at Minecraft 1.20.4, so use NeoForge or Fabric on a current version.

To change loader or version, open JAR Manager under More, choose the loader under Server software and the version under Minecraft version, then press Apply change. The loader and version guide has the full steps. Switching reinstalls the server and keeps your world, though configuration files may be reset, so leave Take a backup first ticked when the confirmation window asks.

Install it

1. Open Mods under Content and keep the Modrinth chip selected in the source chip row at the top of the tab. The Game version filter starts on your server's version.
2. Search for Mutant Monsters and press Install on the one by Fuzs.
3. A window titled "Needs 1 more add-on" (or more on Fabric) lists the libraries above. Press Install all.
4. Restart from the Console tab. The install message ends with "Restart the server to load them".

Open the Installed view to check. Mutant Monsters and its libraries should be listed with no Failed to load badge.

Players need it too

Modrinth marks the mod as required on both the client and the server. Each player installs the same mod and its libraries for their loader and Minecraft version. Join a modded server from your launcher covers the player side, and Fix the mismatched mod channel list error explains the refusal when versions differ. The Export for players button in the Installed view packs the mods players need into one zip.

Try it out

Mutants spawn on their own wherever their ordinary versions can. To see one without waiting, join the server as an operator and run /summon mutantmonsters:mutant_zombie in a spot you don't mind damaging. Operators are set in the Players tab; Whitelist players and set operators shows how.

The project page lists the main rewards: the Hulk Hammer from the Mutant Zombie, Mutant Skeleton Armor crafted from the Mutant Skeleton's bones, a Creeper Minion Egg dropped by the Mutant Creeper, and the Endersoul Hand, which the page says you gain by cutting off the Mutant Enderman's hand.

Settings

The mod uses two settings files, mutantmonsters-common.toml and mutantmonsters-server.toml. On NeoForge 26.3 both appear in the config folder after the first start, and the world folder has no serverconfig folder to check. Stop the server before editing a file in the File Manager.

• mutant_creeper_spawn_weight, mutant_enderman_spawn_weight, mutant_skeleton_spawn_weight and mutant_zombie_spawn_weight are in the common file. They set how often each mutant spawns, as a fraction of the ordinary mob's weight. The default for each is 0.05, which is 5%. Changing them needs a world restart.
• endersoul_hand_teleport_distance is in the server file. It sets how far the Endersoul Hand can teleport you. The default is 256 blocks.

Updating

Make a backup first in the Backups tab. Then press Check for updates in the Installed view. It only looks: if newer builds exist for your server's version, the button becomes Update all (N) and a row with a newer build gets its own Update button. Update all (N) asks you to confirm before it swaps in the newest builds. Restart the server afterwards to load them.

Common problems

• The server stops at startup: open the Console and read the last lines. A missing library is the usual cause. Fix mod and plugin errors on Minecraft covers reading the log.
• No results for your version: the newest builds target Minecraft 26.x and 1.21.x. Check the Game version filter against what JAR Manager shows.
• Players can't join: they are missing the mod or one of its libraries.