Zombie Apocalypse Addon

Turn Minecraft into a configurable zombie survival world where daytime is not automatically safe.

Zombie Apocalypse Addon adds custom zombie waves, hordes, blood moons, day-based difficulty, optional siege behavior, kill milestones, and broad zombie-mod compatibility. It works for a simple survival server out of the box, while still providing deep controls for apocalypse packs.

Quick Info

• Multiplayer: install on the server only. Players can join without the mod.
• Singleplayer: install on the client because singleplayer runs a local server.
• Current targets: NeoForge 1.21.1, NeoForge 1.20.1, and Forge 1.20.1.
• Commands: anyone can read dashboards, help, stats, status pages, and current setting values. Changes require permission level 2.
• Config: config/zombieapocalypseaddon-common.toml.
• Safe defaults: block breaking, block placing, zombie towering, and animal hunting are off.

Start Here

After installing the correct jar, join as an operator and run:

/za

This opens a short dashboard showing the current day, custom waves, light protection, events, scaling, and optional world-pressure features.

For a fast setup, choose one gameplay preset:

/za preset casual
/za preset standard
/za preset hardcore

• Casual: fewer zombies, a 10-day daylight grace, no baby zombies.
• Standard: the recommended balance. A fresh install already uses it.
• Hardcore: faster waves, bigger events, and quicker difficulty growth.

All three keep block breaking, block placing, towering, and animal hunting as you set them, and leave advanced attribute values alone. A preset replaces the settings in this table, so apply it first and tune afterward.

Use /za help for short topic-based help instead of a wall of commands. Press Tab after /za to browse every system and get suggestions for states, values, players, attribute keys, and blocks.

Common Tweaks

Most things players ask for are one command away:

Every on command keeps your other settings. If one value would stop the feature from working, such as a 0% chance, on fixes just that value and tells you what it changed. /za config reset <section> puts a whole section back to its defaults when you want that.

Main Features

• Custom zombie waves around survival players during day and night
• Permanent night-only custom spawning mode
• Optional sunlight immunity
• Optional torch and block-light spawn protection
• Configurable baby zombie chance, including complete disablement
• Natural and manual horde events
• Random and forced blood moons
• Morning day-counter announcements and manual day control
• Day-based health, speed, armor, and equipment scaling, rising daily or in jumps every few days
• Optional bigger waves as difficulty rises, including hordes and blood moons
• Siege nights: let block breaking, placing, and towering run only during hordes and blood moons until a chosen day
• Armor and weapon tiers that accept items from any mod, such as Epic Knights, with an adjustable gear drop chance
• Advanced per-attribute, per-variant, biome, and dimension tuning
• Optional zombie block breaking with conservative safety rules
• Optional limited block placing for steps and one-block gaps
• Optional moving zombie stacks that climb defenses without changing blocks
• Optional animal hunting: zombies hunt animals, eat dropped meat, and permanently grow health — well-fed zombies persist, drop extra loot, and can promote to door-breaking leaders that call reinforcements. Killed horses can rise as zombie horses for zombies to ride
• Biome-aware Husk and Drowned spawning
• Optional Nether and End custom spawning
• Death cooldown protection after a player dies
• Kill tracking and advancements at 250, 1,000, and 3,000 kills
• Configurable bonus drops, including gunpowder
• Spawn effects, debug logging, and live admin controls
• Broad compatibility with zombie and spawn-control mods

Mushroom-field safe zones remain active even if biome variant weighting is turned off. Night pressure only applies in dimensions with a real day/night cycle, so the Nether, End, and other fixed-time dimensions do not receive a permanent night boost. Bonus drops also respect the vanilla doMobLoot gamerule.

What the Default Setup Does

A fresh install uses the Standard preset:

• First day: daytime is safe on day 0 so players can gather gear. From day 1, waves can come day and night.
• Waves: every 6 seconds each survival player has a 50% chance of a wave of 2 zombies at least 12 blocks away within a 30-block range, up to 50 zombies around that player. Nights raise the chance by half.
• Lit bases are safe: custom waves need complete block darkness, so torches and lanterns protect an area.
• No sunlight burning: zombies walk around in daylight.
• Hordes: every 5th day there is a 50% chance of a horde at dusk. It lasts about the whole night, checks for waves every second at three times the chance, and sends 5 zombies per wave.
• Blood moons: 15% of nights. Five times the wave chance and 4 zombies per wave until dawn.
• Getting harder: from day 3 to day 50 zombies gain up to 20% speed and 10 health (5 hearts), and up to 30% wear armor and 20% carry weapons, with better tiers later on.
• Variants: husks 15%, drowned 10%, zombie villagers 5%, baby zombies 5%. Deserts favor husks, water favors drowned, and mushroom fields are safe.
• After a death: spawns near that player are halved for 30 seconds.
• Extras: kill tracking, milestones, spawn sounds and particles, and bonus drops are on.
• Off until you turn them on: block breaking, block placing, towering, animal hunting, and Nether and End spawning.

Player-built lights block the addon's custom waves by default - custom spawns need complete block darkness, so torches and lanterns protect bases. To let zombies spawn in dimmer spots, or ignore light entirely:

/za spawn maxlight 7
/za spawn maxlight -1

This checks block light only. It does not disable daytime waves by itself; use /za spawn daytime off for that.

Essential Commands

Every system is available below /za:

• /za spawn for spawning and main toggles
• /za events and /za bloodmoon for events
• /za day and /za scaling for progression
• /za gear for zombie armor and weapons, including modded items
• /za breaking, /za placing, and /za towering for optional base pressure
• /za hunt for optional animal hunting and zombie growth
• /za stats for kills and milestone reset
• /za attributes for advanced attributes
• /za compatibility for mixed-mod behavior
• /za burn, /za kill, and /za cleanup for utilities

Run any setting name without a value to read its current value. Use on and off for switches; true and false still work for existing command blocks and scripts. All original /z... command roots remain supported.

Feature on commands only turn the feature on, plus any switch it depends on. If a value would leave the feature doing nothing, such as a 0% chance, they fix just that value and say so. Everything else you tuned stays as it is, and /za config reset <section> restores defaults when you want them.

See the full command reference for every subcommand and range.

Custom Spawning

Administrators can control:

• wave chance and interval
• zombies attempted per wave
• nearby cap per player
• minimum and maximum spawn distance
• position attempts
• permanent daytime spawning toggle
• daylight start day
• open-sky requirement
• maximum allowed block light
• zombie variant and baby chances
• night pressure
• biome and dimension behavior

Spawn checks are bounded, staggered where appropriate, and avoid unloaded chunks. With open-sky spawning disabled, the mod searches near the player's height for valid caves and covered spaces instead of only choosing the surface.

For night-only custom spawning, run /za spawn daytime off. Normal night waves, blood moons, and dusk hordes (the default) continue, and manual hordes can be started at night. If you switched hordes to dawn with /za events dusk off, night-only mode pauses them. The Nether, End, and other fixed-time dimensions keep using their own dimension toggles. daylightstart remains available as a separate temporary grace period for servers that want daytime waves to begin later.

Events and Progression

Hordes temporarily raise wave pressure on scheduled days. Blood moons create stronger night pressure. Both have separate chance, size, duration, interval, and multiplier settings available through /za events and /za bloodmoon, and both can be triggered manually. Scheduled hordes arrive at dusk by default and last about the night, or roll at dawn with /za events dusk off. They require custom waves; turning custom waves off cancels active or queued spawn pressure. Night-only mode pauses scheduled dawn hordes and daytime horde waves without disabling night waves or blood moons; dusk-start hordes still run in night-only mode. If both events overlap, their multipliers stack and the larger configured event wave size wins.

Basic day scaling is enough for most servers. /za scaling exposes the progression days and basic full-strength bonuses. /za scaling steps <days> makes strength rise in jumps on the morning after every step day instead of a little each day, and /za scaling extrazombies <count> adds zombies to every wave as strength rises. Advanced profiles can separately tune health, attack damage, movement speed, armor, follow range, and knockback resistance for each variant and environment, with exact per-key ranges shown by /za attributes get <key>.

Scaled zombies draw armor and weapons from four tiers. Tier 1 is most common early and later days favor tiers 3 and 4. The tiers start with vanilla gear, and items from any mod can be added: hold an item and run /za gear add <tier>, or list item IDs in tier1Gear to tier4Gear. Slots are detected automatically, shields are never used, and /za gear preview <tier> spawns a zombie wearing a tier. gearDropChance controls how often that gear drops.

Siege Nights

Hordes can act as siege nights that make the world harder each time. This sends a horde at nightfall every 10th day, lets zombies break and build only during those nights, makes them stronger and more numerous the morning after each one, and from day 50 lets them break and build all the time:

/za events on
/za events interval 10
/za events chance 1
/za events dusk on
/za events duration 10
/za scaling steps 10
/za scaling extrazombies 4
/za breaking on
/za breaking startday 50
/za breaking events on
/za placing on
/za placing startday 50
/za placing events on

on commands keep your other settings, so the order does not matter. Duration is in minutes of play; 10 lasts from dusk to about dawn. Blood moons count as event nights too, so use /za bloodmoon off if only the scheduled sieges should allow breaking and building. /za towering events on works the same way.

Optional Base Pressure

Block breaking, block placing, and towering are independent and disabled by default. No-AI zombies are ignored, and a zombie can complete at most one of these actions during the same tick.

• Block breaking has day gating, hardness limits, protected block categories, target rules, drops, and mobGriefing support.
• Block placing uses a configurable solid block, per-zombie limits, loaded-chunk checks, protection events, and separate step/bridge controls.
• Towering forms real moving passenger stacks when a raised target or genuinely blocked route makes climbing useful. Ordinary ground combat and normal player jumps do not trigger it. The normal preset grows only through the target's block Y level plus one, then moves one top rider at a time to a collision-free floor position after the target stays reachable on the ground. Optional jump attacks never inherit hit or knockback velocity. No blocks are placed or broken.

Administrators can use on to turn a feature on with their own settings (it waits for the feature's start day), dayone to also start it today, and off at any time. events on (for example /za breaking events on) also lets a feature run during hordes and blood moons before its start day. The older dayone aliases remain supported.

Tower controls include /za towering stacksize <count> (0 means no count cap), /za towering maxperplayer <count>, /za towering dynamic <on|off>, /za towering offset <blocks>, /za towering smartdismount <on|off>, /za towering pace <ticks>, and optional jump controls. Mounting and dismounting use loader-correct rider positions and reject blocked spaces instead of putting zombies inside floors or ceilings. /za towering unlimited removes both count and height caps and disables automatic collapse; very tall passenger chains can affect server performance.

Mod Compatibility

The addon automatically recognizes modded Zombie subclasses and supports unusual infected entities through optional tags and exact include/exclude lists.

Compatibility safeguards can respect external spawn rules, avoid duplicate AI or difficulty systems, preserve modded equipment, and honor per-zombie door-breaking permission.

Built-in handling covers:

• Zombie Awareness
• Zombie Horse Spawn
• Mo' Zombies Wave
• More Zombie Villagers
• Zombies Reworked
• Zombie Villagers From Spawner
• Zombie Variants
• Zombies+
• Zombie Proof Doors
• Undead Nights
• The Hordes
• Improved Mobs
• In Control!
• Bad Mobs
• Giant Spawn

Other mods can work automatically when their infected mobs extend Minecraft's normal Zombie class. See the compatibility guide for exact behavior and overrides.

Config That Normal Servers Need

The generated file begins with a START HERE section. For a normal setup, focus on:

• [dayspawning]
• [variants]
• [horde]
• [bloodmoon]
• [scaling]

Leave [compatibility], [attributes], variant profiles, and context profiles at their defaults unless you specifically need deep tuning.

Every setting includes a plain-language description, examples, safe ranges, feature dependencies, and performance warnings where relevant. Remember that 20 ticks equals one second and chances use decimals from 0.0 to 1.0.

In-game commands save right away and never reset other settings. File edits are picked up while the game runs, though editing with the server stopped is safest. If the loader ever resets settings while reading a half-saved file, the mod puts them back and tells online operators.

See the config guide for practical examples.

Server Use

• Singleplayer and private servers for you and your friends: go ahead, no permission needed.
• Anything bigger - public servers, community or network servers, or servers with donations, ranks, or paid perks: ask first. Send me a message on CurseForge or Modrinth with what the server is and how players get the mod.
• Always: players download the mod from its official Modrinth or CurseForge page. Do not re-host the jar or publish modified builds. Config changes, datapacks, and separate add-ons that depend on this mod without copying its code or assets are fine.

Safe Removal

Run this before temporarily or permanently removing the mod:

/za cleanup uninstall

Then stop the server and remove the jar. The command removes loaded zombie-class mobs, resets event state, and disables active addon systems.

Help and Documentation

• Wiki home
• Commands
• Config guide
• Troubleshooting
• Compatibility
• Safe uninstall

If you want constant zombie pressure without forcing every server into the same difficulty, this mod is built for that.