Custom mobs and bosses: MythicMobs for a Minecraft server

In short: drop MythicMobs into plugins/, start the server and describe a mob in plugins/MythicMobs/Mobs/<file>.yml — only an internal name and a Type are required. After editing run /mm reload and summon the mob with /mm mobs spawn <name>. Skills go in Skills/, items in Items/, drop tables in DropTables/. The free version does almost everything; Premium adds math and placeholders in numbers, extra mechanics and development builds.

What MythicMobs does#

According to its docs, MythicMobs changes any attribute of any non-player entity and creates new mobs — from a tougher zombie to a scripted boss fight. Everything is configured in files, with no client mods.

• Attributes — health, damage, armor, speed, follow and combat range.
• Skills — mechanics (damage, ignite, summon, teleport, particles, sounds), targeters, triggers and conditions: when an ability fires and who it hits.
• Equipment and items — custom items with enchantments and attributes that mobs wear or drop.
• Drops — plain lists and drop tables with conditions; besides items: experience, money through Vault, mcMMO experience or a console command.
• Damage modifiers — immune to fire, double damage from arrows and so on.
• Spawners and random spawns — your own spawn points with timers and conditions, or a replacement for vanilla spawning.
• Levels, threat tables, AI and factions — a mob gets stronger with its level, picks targets by threat, and mobs of different factions fight each other.
• Looks — disguise as another entity through LibsDisguises, and custom 3D models through the separate ModelEngine plugin.

Free version and Premium#

The free version of MythicMobs downloads from Modrinth and the MythicCraft site; Premium is bought on the MythicCraft site. The wiki's Premium page lists the difference:

Installing and versions#

On Modrinth, version 5.13.0 (22 July 2026) is marked for Paper, Spigot and Folia and for Minecraft up to 26.2. Put the jar into plugins/ and restart — the general rules are in how to install a plugin. On first start MythicMobs creates its folder with example mobs, items and spawns, which make a good starting point.

Where the files live#

Items from Items/ are worn and dropped by mobs, and /mm items get hands them to a player. For items with their own abilities, blocks and furniture, MythicCraft makes a separate plugin, MythicCrucible, on the same skill system — how custom items work on a server in general is covered in custom items. Drops can pay money through Vault, so make sure bosses don't turn into a money printer: see server economy.

A first boss: mob, skill and drops#

The example follows the step-by-step guide in the official wiki: a Skeleton King with 500 health, summoned minions and custom drops. The internal name (SkeletonKing) must be unique and contain no spaces — commands use it to summon the mob.

SkeletonKing:
  Type: WITHER_SKELETON
  Display: '&6Skeleton King'
  Health: 500
  Damage: 10
  Options:
    AlwaysShowName: true
    MovementSpeed: 0.2
    PreventOtherDrops: true
  Equipment:
  - IRON_BOOTS FEET
  Drops:
  - SkeletonKingDrops
  Skills:
  - skill{s=SummonSkeletons} @self 0.1

SummonSkeletons:
  Cooldown: 15
  Skills:
  - message{m="<caster.name><&co> Arise, my minions!"} @PlayersInRadius{r=40}
  - delay 20
  - summon{mob=SKELETON;amount=2;radius=5;repeat=2;repeatInterval=20} @Self

SkeletonKingDrops:
  Drops:
  - experience 100-150 1
  - GOLD_NUGGET 32-64 1
  - DIAMOND 1-12 0.8

A drop is written as <what> <amount> <chance>: the amount can be a range, the chance a number from 0 to 1. PreventOtherDrops: true removes the vanilla drops, so the king doesn't also drop ordinary bones. Colors in Display use the same & codes as chat; the color codes tool helps pick them.

MythicMobs commands#

Full access comes with the mythicmobs.admin permission, single commands with mythicmobs.command.<command>. The developers explain why there are so few permissions: nearly every MythicMobs command can be abused. So give them to admins only, through LuckPerms. And don't test mobs in creative: the Troubleshooting page says it breaks most things — test in survival.

Spawners and random spawns#

A spawner is a point where a mob appears on a timer — good for dungeons and arenas. Create one with /mm s create or a file in Spawners/. One caveat from the docs: while the server runs, a loaded spawner file can only be changed with in-game commands — to edit it in a text editor, stop the server first.

Random spawns live in RandomSpawns/: Action: ADD adds mobs with MythicMobs' own algorithm, REPLACE swaps vanilla spawns, DENY blocks them. ADD needs GenerateSpawnPoints: true in config/config-spawning.yml, and REPLACE does nothing if vanilla mob spawning is turned off by a game rule — see game rules.

Performance#

• Leave `CheckForPlayers` alone. At true a spawner stays idle until players come near — the docs recommend it for performance.
• Let mobs despawn. The Despawn option is on by default, and the wiki says to keep it on if you use a lot of spawners, or entities will overwhelm the server. PERSISTENT mode saves a mob in the world across restarts — keep it for bosses, not for regular mobs.
• Count your mobs. /mm mobs listactive and /mm mobs stats show how many MythicMobs mobs are alive right now.
• Profile instead of guessing. If TPS dropped after new bosses, take a spark profile: the «Sources» view shows how much of the tick MythicMobs itself takes. General diagnosis is in why the server lags.

Bosses and the anticheat#

To the server, a boss with skills is a fair fight: damage, knockback from the throw mechanic and teleporting to the player all come from the plugin. But a player who farms the boss with KillAura, Reach or an AutoClicker devalues both the drops and the economy they flow into. DGuard — the best anticheat for a modern Minecraft server — checks all 47 cheat types of the comparison, combat cheats included, gathers evidence and doesn't rush to a verdict, while you set how strict the punishments are.

DGuard runs on Paper and Leaf 1.21–26.3 next to the latest PacketEvents release; the main version is 1.21.11, and the other versions are supported but not yet proven on live servers. Before launching a new boss whose skills move players around, run the fight on a test server with the anticheat and look at the punishment log. What each cheat does and how to spot it is in the cheats encyclopedia.

FAQ#