Random Sized Mobs

Give familiar mobs a little more variety. Random Sized Mobs assigns each creature a persistent size, then balances that size with small changes to health, damage, movement and supported attack cooldowns. Larger mobs hit harder and take more punishment, while smaller mobs are quicker and more fragile.

The default range is 0.75× to 1.25×. You can keep that subtle variation or choose your own limits with gamerules. The mod applies to existing mobs as well as newly spawned ones, and supports vanilla mobs and compatible mobs from other mods.

Features

• Individual sizes: changes mob models and collision dimensions, while preserving natural differences such as baby and adult sizes.
• Gentle balance changes: larger mobs gain health and damage at the cost of movement speed and supported attack speed; smaller mobs receive the opposite tradeoff.
• Persistent results: saving, restarting or unloading a chunk keeps a mob's size. Changing the configured range keeps its relative position within that range.
• Consistent damage scaling: damage attributed to a mob is adjusted once, including melee, projectiles, explosions and special attacks.
• Health that stays proportional: changing the size range preserves each mob's remaining health percentage.
• Live world settings: loaded mobs adopt changed gamerules within about one second. Unloaded mobs update when they load.
• Compatibility with normal mob systems: existing attribute modifiers from other mods are preserved, and missing optional attributes are handled safely.
• No player resizing: players and armor stands are excluded.

Default balance

These are the balancing factors. Attack cooldowns are rounded to whole ticks, and bow draw time or crossbow charging also affects the final attack frequency. Standard melee, ranged, bow and crossbow goal cooldowns are supported. Special AI timers, including some vanilla boss, brain-driven and custom mod attacks, may retain their own timing.

Configure the size range

Gamerules use whole-number percentages: 75 means 0.75×, 100 means normal size, and 125 means 1.25×.

Minecraft 1.12.2 through 1.21.1

/gamerule rsmMinSize 75
/gamerule rsmMaxSize 125

Minecraft 26.x

/gamerule randomsizedmobs:min_size 75
/gamerule randomsizedmobs:max_size 125

• Default: minimum 75, maximum 125.
• Supported limits: 25 to 400, corresponding to 0.25× to 4×.
• Normal size: set both limits to 100.
• One fixed size: set both limits to the same value.
• Reversed limits: treated as the same interval, with the lower value used as the minimum.

Settings are saved with the world. Minecraft 26.x rejects values outside the supported range; older versions clamp them when applying the size calculation. A mob's individual size is derived from its UUID, so it does not reroll whenever you reload the world.

Supported versions and loaders

The 1.0.0 package contains 18 separate builds. Choose the file matching your exact Minecraft version and loader.

Installation

1. Install the matching Minecraft version and mod loader.
2. For Fabric, also install the matching Fabric API.
3. Place the appropriate Random Sized Mobs JAR in the instance's mods folder. Use only one build per instance.
4. For multiplayer, install the matching mod on both the server and every client.
5. Launch the game and open your world. Use the gamerules above to adjust the range.

Languages

Gamerule labels are included in 14 languages: English (US), Portuguese (Brazil), Portuguese (Portugal), Spanish (Spain), French, German, Italian, Russian, Polish, Turkish, Japanese, Korean, Simplified Chinese and Traditional Chinese.

Mod compatibility

Random Sized Mobs works through Minecraft's base mob systems. Modded creatures that use standard attributes, dimensions and rendering paths can participate automatically. Mods with their own rendering, multipart entities, attribute frameworks or attack scheduling may require a specific compatibility adapter.

Damage scaling applies when the damage source identifies a mob as the attacker. Environmental or otherwise unowned damage remains unchanged. Custom AI may retain its own attack timing even when its damage is adjusted.