Mood Contagion

Mobs now carry a hidden emotional state: CALM, PANIC, or RAGE. Combat seeds the state, it spreads to nearby mobs of the same type, and it fades back to calm over time.

• Hit a mob and it panics. It runs from you, and the fear spreads to others nearby: one scared sheep can set off the whole flock.
• Hit a wolf, a bee, or any hostile and it rages instead. Raging mobs move faster and hit harder, and a neutral animal will turn and come for you. Rage spreads the same way.
• Kill a mob and nearby mobs of the same type panic.

Panicking mobs give off yellow particles and enraged mobs give off red ones, so you can read the state at a glance.

How it works

• Each mob's state and a timestamp are stored on the mob in its PersistentDataContainer, so moods survive chunk unloads and restarts and never leak memory.
• A task runs about once a second and processes mobs round-robin with a per-tick budget, so the feature stays cheap on TPS no matter how crowded the world is.
• Emotional mobs have a chance to infect same-type neighbours within a radius. Moods decay back to calm after a configurable time.
• PANIC adds Speed and makes the mob flee the nearest player. RAGE adds Speed and Strength, and makes neutral mobs target the nearest player.

Commands

Command	Description	Permission
/moodcontagion info	Show the current tunables.	moodcontagion.use (default: all)
/moodcontagion here	Count CALM/PANIC/RAGE mobs within 16 blocks of you.	moodcontagion.admin (default: OP)
/moodcontagion reload	Reload config.yml.	moodcontagion.admin (default: OP)

Aliases: /mood, /contagion.

Permissions

Node	Default	Grants
moodcontagion.use	everyone	the info and here sub-commands
moodcontagion.admin	OP	reload (and includes moodcontagion.use)

Configuration (config.yml)

Key	Default	Meaning
spread-radius	8.0	Blocks within which a mood spreads to same-type mobs (also the flee/retarget scan range, x2).
spread-chance	0.35	Per-neighbour, per-second chance to infect a same-type neighbour.
decay-seconds	12	How long an emotional mood lasts before it decays to CALM.
max-processed-per-tick	40	TPS guard: max mobs handled per processing pass (round-robin).
panic-flee-speed	0.45	How hard a PANIC mob is shoved away from the nearest player.
max-horizontal-velocity	1.5	Hard cap on any velocity the plugin sets (anti-launch safety).
death-seed-radius	8	Blocks around a dying mob in which same-type mobs are seeded PANIC.
effects.enabled	true	Master switch for all potion effects.
effects.speed	true	PANIC and RAGE mobs gain Speed.
effects.strength	true	RAGE mobs gain Strength.
effects.rage-retarget	true	Neutral RAGE mobs target the nearest player (only when they have no valid target).
effects.particles	true	Mood-coloured particle puffs above emotional mobs.

All values are clamped to safe ranges on load.

Compatibility

Paper, Spigot, Bukkit, and Purpur 1.21.1 to 1.21.11 and the 26.1.x line (verified on 26.1.2), Java 21. Built against the Spigot API with no Paper-only classes, so the single jar works on all four server types.

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Original concept, an internal test idea. Not sourced from a Reddit post.