Mobs Love Darkness

A Fabric mod for Minecraft 1.20.1, 1.21.1 and 1.21.11 that gives certain mobs a chance to fixate on and destroy nearby light sources, creating dangerous dark zones and rewarding players who pay attention.

What it does

Some mobs will occasionally lock onto nearby torches, lanterns, and campfires and attempt to destroy them. A fixated mob glows and emits soul fire particles, giving an observant player a chance to react before their lighting is gone. Once the mob reaches the light source it breaks it, playing a distinctive sound and returning to normal behavior in the newly created darkness.

Phantoms may occasionally destroy exposed torches during their swooping attacks, making open-air lighting somewhat vulnerable at night — but their erratic flight means covered lighting remains relatively safe.

Everything is highly configurable.

Features

• Configurable list of eligible mob types — any mob can be added via config
• Configurable list of targetable blocks — works with any block ID including modded blocks
• Per-mob-type goal assignment chance — phantoms can be tuned separately from high-spawn mobs like zombies
• Optional glowing effect on fixated mobs for player readability
• Optional soul fire particle trail while fixating
• Optional distinctive sounds on fixation start and light source destruction
• Unreachable targets are blacklisted per-mob to prevent stuck behavior
• Block protection mod compatible — protected blocks are detected and blacklisted gracefully
• All behavior is server-side only, no client installation required for multiplayer

Default behavior

By default, the following mobs are eligible for the light fixation goal:

Mob Default eligibility chance Zombie 5% Husk 5% Zombie Villager 5% Zombified Piglin 5% Phantom 75%

The following blocks are targeted by default:

• Torch / Wall Torch
• Lantern
• Soul Torch / Soul Lantern
• Campfire / Soul Campfire

Configuration

The config file is generated at config/mobs-love-darkness.json5 on first launch. All fields include descriptions and valid ranges directly in the file.

Config Default Description LightSourceSearchRadius 16 Block radius to search for light sources. Range: 1–128 LightSourceSearchRadiusVertical 4 Vertical block radius to search for light sources. Range: 1–128 LightSourceBreakTimeTicks 20 Ticks to break a light source (20 ticks = 1 second). Range: 1–1200 LightFixationChance 0.05 Chance per second that an eligible mob fixates on a nearby light source. Range: 0.0–1.0 LightFixationSpeedMultiplier 0.85 Movement speed multiplier while fixating (1.0 = normal speed). Range: 0.1–10.0 LightFixationCooldownTicks 200 Ticks before a mob can fixate again after destroying a light source. Range: 0–72000 LightFixationMaxGoalTicks 600 Maximum ticks spent on a single fixation attempt before giving up. Range: 100–72000 LightFixationGoalPriority 3 Goal priority (lower = higher priority, vanilla zombie attack = 2). Range: 1–10 EnableParticles true Soul fire particle trail on fixated mobs EnableSounds true Sounds on fixation start and light source destruction EnableLightFixationGlowEffect true Glowing outline on fixated mobs TargetableLightSources see above List of block IDs to target, including modded blocks LightFixationEligibilityChancePerMobType see above Per-mob-type chance to receive the goal on spawn

Performance guidance

Search cost scales cubically with radius — a radius of 128 checks ~500x more blocks than a radius of 16. Balance search radius against mob eligibility:

Search radius Recommended max eligible mobs 16 (default) ~50 32 ~20 64 ~5 128 ~1-2

LightSourceSearchRadiusVertical (default: 4) also contributes to search cost. Increasing it significantly will reduce performance — keep it low unless your use case specifically requires searching underground.

These are rough guidelines. Actual impact depends on hardware and other mods.

Adding modded mobs and blocks

Any valid block or entity registry ID works in the config lists:

"LightFixationEligibilityChancePerMobType": { "minecraft:zombie": 0.05, "minecraft:phantom": 0.75, "alexsmobs:warped_mosco": 0.10 }, "TargetableLightSources": [ "minecraft:torch", "minecraft:wall_torch", "supplementaries:oil_lamp" ]

Compatibility

Game rules

• This mod respects the mobGriefing game rule. If mobGriefing is disabled when a mob spawns, it will not receive the light fixation goal. Mobs that already have the goal when mobGriefing is disabled will stand down gracefully without breaking blocks.

Works with:

• Sodium, Iris, Lithium, and other performance mods
• Mods that add new mob types — add them via config
• Mods that add new light source blocks — add them via config

Does not affect:

• Client-side dynamic lights from shader mods — only actual world blocks are targeted
• Bedrock Edition — Java only

Potential conflicts:

• Mods that completely replace mob AI goal selectors may prevent the goal from being injected
• If goal priority conflicts with another mod, adjust LightFixationGoalPriority in config (vanilla zombie attack goal is priority 2)

Block protection mods (GriefPrevention, FTB Chunks, etc.) — protected blocks are detected after a break attempt and blacklisted, preventing repeated attempts. Note: FTB Chunks mob griefing protection on Fabric only covers Endermen by default and will not prevent this mod's block breaking — use the mobGriefing game rule for global protection instead.

Known limitations

• There is no distinction between player-placed and world-generated blocks — blocks that are naturally generated can also be targeted
• Phantoms have imprecise torch-targeting due to their flight navigation — this is somewhat by design, as accurate phantom targeting would be difficult to counter
• Disabling the mobGriefing game rule prevents new mobs from receiving the goal and prevents blocks from being broken by mobs that already have it

GitHub

https://github.com/AndartaMC/mobs-love-darkness

License

MIT — feel free to include this mod in modpacks.