Zombie Apocalypse Addon - Everything Can Be Customized

Turn your Minecraft world into a long-term zombie survival scenario where daytime is no longer safe.

Zombie Apocalypse Addon replaces the usual "survive the night, relax during the day" loop with constant pressure, escalating danger, event surges, and deep server-side control. Zombie-class mobs can spawn around players during both day and night, hordes and blood moons can raise the pressure even higher, and enemy stats can scale as the world gets older.

This is not just "more zombies." It is a configurable zombie survival framework built for servers, challenge worlds, apocalypse packs, and long-running PvE worlds.

Quick Info

• Multiplayer: install on the server only
• Client install: optional for multiplayer
• Singleplayer: install on the client, because singleplayer runs an integrated server
• Current targets: NeoForge 1.21.1, NeoForge 1.20.1, and Forge 1.20.1
• All admin commands require OP level 2
• Most major systems can be changed live with commands

What This Mod Adds

• Custom zombie-class spawning around players during both day and night
• Optional zombie sunlight immunity
• Optional block-light spawn protection for torches, lanterns, glowstone, and similar light sources
• Optional baby zombie spawn control
• Optional zombie block breaking with day gating and safety controls
• Natural and manual horde events
• Random and forced blood moon nights
• Morning day-counter announcements
• Manual apocalypse day control
• Early-world daylight spawn grace period
• Day-based difficulty progression
• Advanced attribute tuning for spawned zombie-class mobs
• Biome and dimension-based spawn and stat behavior
• Loaded-chunk-aware custom spawn placement to reduce server stalls
• Temporary spawn pressure relief after player death
• Persistent kill tracking and milestone advancements
• Optional bonus zombie drops, including configurable gunpowder drops
• Optional spawn particles and sounds
• Detailed config comments for easier setup

Zombie-class mobs include:

• Zombie
• Husk
• Drowned
• Zombie Villager

Core Gameplay Systems

Constant Threat Spawning

Custom spawn waves can run near survival players all day and night.

You can control:

• how often spawn checks happen
• the chance of a spawn wave
• how many mobs are attempted per wave
• the per-player nearby zombie cap
• spawn range around each player
• minimum spawn distance
• spawn-position attempts per mob
• whether overworld spawns require open sky
• whether block light should stop custom spawns
• whether baby zombie spawns are allowed

This lets you tune the mod for anything from a tense vanilla-style survival world to a full hardcore apocalypse server.

Horde Events

Hordes are timed high-pressure zombie surges with their own settings.

You can configure:

• day interval for horde scheduling
• chance a scheduled horde actually starts
• horde duration
• event spawn interval
• horde wave size
• horde spawn multiplier
• on-screen event notifications

Admins can also start or stop hordes manually.

Blood Moon Nights

Blood moons can happen randomly at night or be forced manually.

During a blood moon:

• spawn pressure increases heavily
• event multipliers stack with normal spawning systems
• players can receive on-screen alerts when notifications are enabled

Day Counter and Day Control

The mod includes an apocalypse day counter system.

• Show the current day on screen every morning
• Toggle morning day announcements in config or by command
• Check the current day with /zday status
• Set the apocalypse day manually with /zday set <day>

When the day is changed, apocalypse event scheduling state is reset so horde and blood moon logic stays consistent.

Early-Day Daylight Spawn Grace

If you want the beginning of a world to be less punishing during daylight, daytime custom spawning can be delayed until a chosen day.

Examples:

• 0 = daytime spawning is active immediately
• 10 = daytime spawning only starts on day 10
• 15 = daytime spawning only starts on day 15

This can be changed in the config or live with command.

Light-Based Spawn Protection

You can optionally make custom spawns respect block light from torches, lanterns, glowstone, and similar light sources.

Examples:

• -1 = ignore block light and keep the default apocalypse behavior
• 0 = only spawn in complete block darkness
• 7 = classic hostile-mob-style limit

This checks block light only. Sunlight is ignored so daytime spawning can still work.

Optional Zombie Block Breaking

Zombies can be allowed to break blocks after a chosen apocalypse day.

This system is disabled by default because it can damage bases. If a server owner enables it, they can tune:

• start day
• check interval
• break chance
• break range
• max block hardness
• whether broken blocks drop items
• whether zombies need a target
• whether zombies need to be blocked or chasing a covered target
• whether the vanilla mobGriefing gamerule can stop it
• whether containers, modded block entities, tool-required blocks, and light sources are protected

The default hardness limit is meant for soft blocks and wooden doors, while stone, ores, containers, machines, and light blocks stay protected unless you loosen the safety settings.

Quick setup:

• /zblockbreak dayone = enable it and make it active immediately
• /zblockbreak enabled true = enable it while still respecting the configured start day
• /zblockbreak startday 10 = let zombies start breaking blocks on day 10

The defaults are intentionally safer: no block breaking unless enabled, no container/machine breaking, no light-source breaking, no tool-required block breaking, and no item drops from broken blocks.

Difficulty Scaling

Zombie pressure can scale as the world progresses.

The mod supports:

• scaling start day
• maximum scaling day
• legacy speed and health scaling
• full attribute scaling through the advanced attribute system

This creates a stronger long-term survival curve instead of flat difficulty.

Variant, Biome, and Dimension Logic

Spawn composition and stat behavior can change based on where mobs spawn.

Supported behavior includes:

• more husks in desert-like biomes
• more drowned in water-heavy biomes
• mushroom fields as optional safe zones
• optional custom spawning in the Nether and End
• biome and dimension context multipliers for attributes

Death Cooldown

After a player dies, spawn pressure can be reduced temporarily to avoid repeated instant deaths.

This is useful on servers and harder setups where nonstop pressure can otherwise snowball too hard.

Stats, Milestones, Drops, and Effects

The mod includes support systems around the main apocalypse gameplay:

• persistent zombie kill tracking
• death cooldown tracking
• optional bonus zombie drops
• configurable gunpowder drops from zombie-class mobs
• optional spawn particles and sounds
• optional debug logging
• zombie kill milestone advancements at 250, 1000, and 3000 kills

Advanced Attribute System

One of the largest systems in the mod is the attribute pipeline for zombie-class mobs when they enter the world.

Supported attributes:

• Health
• Attack Damage
• Movement Speed
• Armor
• Follow Range
• Knockback Resistance

Attribute Flow

For each affected mob, values are applied in this order:

1. Start from vanilla base values
2. Apply global base profile
3. Apply per-variant profile if enabled
4. Apply biome and dimension context multipliers if enabled
5. Apply attribute-based day scaling if enabled
6. Apply legacy health and speed scaling compatibility values
7. Clamp to safe limits

Why This Matters

This lets you build very specific difficulty behavior.

Examples:

• all spawned mobs are slightly faster globally
• husks hit harder than standard zombies
• drowned are tankier in water biomes
• Nether spawns are faster and more aggressive
• late-game mobs detect players from farther away

You can keep the system simple, or tune it deeply for server balance.

Commands

All commands require OP level 2.

General

• /zhelp - Show built-in help
• /zburn <true|false> - Control whether zombies burn in daylight
• /zkill - Remove zombie-class entities from loaded levels
• /zcleanup - Remove loaded zombie leftovers and reset apocalypse event state
• /zcleanup uninstall - Cleanup plus disable spawning, events, scaling, attributes, block breaking, sunlight immunity, extra drops, and cooldowns before removal

Day Control

• /zday - Show current world day status
• /zday status - Show current world day and time-of-day
• /zday set <day> - Set the apocalypse day counter

Events

• /zhorde start - Start a horde immediately
• /zhorde stop - Stop the active horde
• /zhorde status - Show horde, blood moon, and multiplier state
• /zbloodmoon - Force a blood moon now or queue it for tonight

Stats

• /zstats - Show your own stats or server summary from console
• /zstats <player> - Show stats for a specific player
• /zstats all - Show server totals
• /zstats clear - Clear tracked stats, cooldowns, and milestone progress

Spawn Settings

• /zdayspawn status - Show current spawn settings
• /zdayspawn enabled <true|false> - Toggle custom spawning
• /zdayspawn chance <0.0-1.0> - Set spawn-wave chance
• /zdayspawn babychance <0.0-1.0> - Set baby zombie chance, use 0.0 to disable new baby zombie-class spawns
• /zdayspawn interval <ticks> - Set normal spawn interval
• /zdayspawn eventinterval <ticks> - Set horde/blood moon spawn interval
• /zdayspawn amount <1-50> - Set mobs attempted per wave
• /zdayspawn attempts <1-40> - Set spawn-position attempts per mob
• /zdayspawn max <1-500> - Set nearby zombie cap per player
• /zdayspawn range <16-128> - Set spawn range around players
• /zdayspawn mindist <8-64> - Set minimum spawn distance from players
• /zdayspawn daylightstart <day> - Delay daytime custom spawning until a chosen day
• /zdayspawn maxlight <-1-15> - Set maximum block light for custom spawns, use -1 to ignore block light
• /zdayspawn sky <true|false> - Require open sky for overworld custom spawns
• /zdayspawn variants <true|false> - Toggle zombie variant spawning
• /zdayspawn nightboost <true|false> - Toggle night spawn boost
• /zdayspawn horde <true|false> - Toggle horde system
• /zdayspawn hordechance <0.0-1.0> - Set scheduled horde chance
• /zdayspawn daycounter <true|false> - Toggle morning day-counter titles
• /zdayspawn bloodmoon <true|false> - Toggle random blood moons
• /zdayspawn scaling <true|false> - Toggle day-based scaling
• /zdayspawn attributes <true|false> - Toggle advanced attributes
• /zdayspawn attributescaling <true|false> - Toggle attribute day scaling
• /zdayspawn variantprofiles <true|false> - Toggle per-variant attribute profiles
• /zdayspawn contextprofiles <true|false> - Toggle biome/dimension context profiles
• /zdayspawn biomes <true|false> - Toggle biome spawn modifiers
• /zdayspawn nether <true|false> - Allow custom spawning in the Nether
• /zdayspawn end <true|false> - Allow custom spawning in the End
• /zdayspawn cooldown <true|false> - Toggle death cooldown system
• /zdayspawn effects <true|false> - Toggle spawn particles and sounds
• /zdayspawn debug <true|false> - Toggle debug logging

Block Breaking

• /zblockbreak - Show current zombie block-breaking settings
• /zblockbreak status - Show current zombie block-breaking settings
• /zblockbreak dayone - Enable zombie block breaking and set the start day to 0
• /zblockbreak enabled <true|false> - Toggle zombie block breaking
• /zblockbreak startday <day> - Set the day when block breaking can start
• /zblockbreak interval <ticks> - Set how often each zombie can attempt block breaking
• /zblockbreak chance <0.0-1.0> - Set the chance per scheduled block-breaking check
• /zblockbreak range <1-4> - Set how far in front of the zombie it checks
• /zblockbreak hardness <0.0-50.0> - Set the maximum block hardness zombies can break
• /zblockbreak drops <true|false> - Toggle item drops from zombie-broken blocks
• /zblockbreak target <true|false> - Require zombies to have a valid target before breaking
• /zblockbreak obstacle <true|false> - Require a blocked path or covered target before breaking
• /zblockbreak mobgriefing <true|false> - Make mobGriefing and loader mob-griefing events control this feature
• /zblockbreak containers <true|false> - Allow or block breaking chests, furnaces, and block-entity blocks
• /zblockbreak toolblocks <true|false> - Allow or block breaking blocks that require the correct tool
• /zblockbreak lights <true|false> - Allow or block breaking light-emitting blocks

Scaling

• /zscaling status - Show current scaling state

Live Attribute Tuning

• /zattr status - Show attribute system status
• /zattr keys - Show key format help
• /zattr keys all - Show all supported numeric and toggle keys
• /zattr get <key> - Read a numeric attribute value
• /zattr set <key> <value> - Set a numeric attribute value
• /zattr toggle <key> <true|false> - Change a supported boolean attribute toggle

/zattr Key Groups

Numeric key groups:

• base.<health|attack|speed|armor|follow|knockback>.<multiplier|bonus>
• scale.<health|attack|speed|armor|follow|knockback>.<multiplier|bonus>
• variant.<zombie|husk|drowned|villager>.<health|attack|speed|armor|follow|knockback>.<multiplier|bonus>
• context.<desert|water|mushroom|nether|end>.<health|attack|speed|armor|follow|knockback>.multiplier
• legacy.<speedMultiplier|healthBonus>

Toggle keys:

• attributes.enabled
• attributes.scaling
• attributes.variantProfiles
• attributes.contextProfiles

If you are unsure what key to use, run:

• /zattr keys all

Config and Tuning

The config file is designed to be readable and includes comments, safe ranges, and explanations for new users.

You can use it for:

• a more hostile vanilla-style survival world
• a PvE server with escalating danger
• a challenge pack apocalypse setup
• a long-running world with increasing pressure over time
• a softer early game that becomes harder later
• a brutal server where day and night are both dangerous
• an optional base-pressure setup where zombies can break selected blocks after a chosen day

Most major settings can also be changed live with commands, which makes balancing much easier during active testing.

Suggested Starting Points

For a lighter survival world:

• delay daylight spawning with daylightstart
• keep horde chance low
• keep scaling slow
• keep baby zombie chance low or disabled

For a hardcore apocalypse world:

• enable day and night custom spawning
• enable hordes and blood moons
• enable scaling and advanced attributes
• increase event wave size and event multipliers
• optionally enable /zblockbreak dayone or set a later /zblockbreak startday

Installation Notes

• Multiplayer servers only need the mod installed on the server.
• Players can join without installing the mod on their client.
• For singleplayer, install it on the client.
• Use the NeoForge 1.21.1 file for Minecraft 1.21.1 NeoForge servers.
• Use the NeoForge 1.20.1 file for Minecraft 1.20.1 NeoForge servers.
• Use the Forge 1.20.1 file for Minecraft 1.20.1 Forge servers.
• Back up your world before changing major spawn or scaling settings.

If you want a configurable zombie apocalypse system with constant pressure, escalating events, live admin controls, and deep stat tuning, this mod is built for exactly that.

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 view /za, /zhelp, and /zstats; changing settings requires permission level 2.
• Config: config/zombieapocalypseaddon-common.toml.
• Safe defaults: block breaking, block placing, and zombie towering 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, day-10 daylight grace, no baby zombies, and torch-protected bases.
• Standard: recommended balance for most survival servers.
• Hardcore: faster waves, larger events, and quicker difficulty growth.

Presets also restore a safe spawn range, minimum distance, attempt count, and open-sky rule, so an old impossible distance setup cannot break the selected preset. They never enable block breaking, block placing, or towering, and they leave advanced attribute values alone.

Use /za help for short topic-based help instead of a wall of commands.

Main Features

• Custom zombie waves around survival players during day and night
• 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
• 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 crowd-based zombie towering without block changes
• 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

The standard setup attempts two zombies with a 50% wave chance every six seconds. It limits nearby pressure per player, increases pressure at night, enables natural events and progression, and keeps destructive features disabled.

Player-built lights do not block the addon's custom waves by default. If you want torches and similar blocks to protect bases, use the Casual preset or set:

/zdayspawn maxlight 7

This checks block light only. Sunlight remains ignored for custom daytime spawning.

Essential Commands

Detailed command families remain available:

• /zdayspawn for spawning and main toggles
• /zhorde and /zbloodmoon for events
• /zday and /zscaling for progression
• /zblockbreak, /zblockplace, and /ztower for optional base pressure
• /zstats for kills and milestone reset
• /zattr for advanced attributes
• /zcompat for mixed-mod behavior
• /zburn, /zkill, and /zcleanup for utilities

Bare status commands now show their current settings. Optional siege commands accept simple on and off forms.

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
• 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.

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, and both can be triggered manually. They require custom waves; turning custom waves off cancels active or queued spawn pressure. If both events overlap, their multipliers stack and the larger configured event wave size wins.

Basic day scaling is enough for most servers. Advanced profiles can separately tune health, attack damage, movement speed, armor, follow range, and knockback resistance for each variant and environment.

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 lets a blocked zombie crowd climb without placing or breaking anything.

Administrators can enable each feature immediately with dayone, use on while preserving its configured start day, or use off at any time.

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.

See the config guide for practical examples.

Safe Removal

Run this before temporarily or permanently removing the mod:

/zcleanup 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.