Magical gene / no coat effect

Holy ward

Hostile mobs do not appear near this horse. Not pushed away — they never spawn in the first place, out to a radius written on the allele copy, at least eight blocks and never more than sixteen.

Built, and not yet seen in game

The gene, its inheritance and its founder table exist and are covered by the test suite; the translator that turns it into behaviour was written against the 26.1.2 sources and is flagged unverified in its own comments. Nothing on this page has been watched happening to a horse. What to look at, and what is most likely to be wrong, is on To be verified.

What it does

CombinationOutcome
Hly/Hlyhostile mobs cannot spawn within the radius
anything elsenothing

A camp that walks

This is the most straightforwardly useful gene in the magical set. Anywhere the horse is standing is somewhere nothing appears — a mining camp, an overnight stop, a half-built base with no lighting yet.

Sixteen blocks, and no further

The radius is epigenetic and drifts with breeding, but it is capped. Uncapped, a well-bred horse would be a permanent peaceful-mode bubble over a whole base and every other defensive gene would stop mattering.

What it actually guards

Monsters never spawn naturally within 24 blocks of a player in the first place, and the ward is smaller than that. So while you are standing beside your horse it changes nothing you would notice — the ground around you was already safe. What it guards is the horse’s patch when you are not there: a paddock you can see from the house, a field on the far side of the farm. To watch it work, turn on debug.announce, stand well back, and look for the purple “spawn refused” lines in chat. Whether it should reach further is an open question (gap 180).

It is not the same as intimidating

Intimidating pushes out what is already there. This stops anything arriving. A horse with both is genuinely safe ground.

Health

None. It protects and costs nothing.

Gene key
horsegenetics.holy_ward
Alleles
Hly warding, n
Inheritance
homozygous recessive
Reaches the game as
a spawn-suppression aura
Epigenetic
radius, minimum 8, capped at 16
Coat effect
none, ever
Cancel natural spawns only, or it silently breaks mob farms

Check the spawn reason. Cancelling spawner-block, spawn-egg, breeding, structure or command spawns breaks the player’s mob farm, other mods’ spawners, and any quest or event that places a mob — and it breaks them invisibly, because nothing errors. Only natural spawning is this gene’s business.

The handler runs on every spawn attempt in the world

This is the only effect in the mod that hooks a global, high-frequency event rather than the horse tick. Iterating horses per spawn attempt is a genuine tick cost on a busy server. Cache the warding positions per level per tick and early-out on an AABB test before doing anything else.

The cap is a balance decision, not a placeholder

Sixteen blocks was chosen so the ward covers a camp and not a base. Raising it later is a gameplay change that quietly retires every other defensive gene.

It interacts with spawner, deliberately

Because spawner is required to go through the normal spawn path, a warding horse standing next to a spawning one suppresses it. That is the correct behaviour and it falls out for free — provided spawner does not shortcut the event.

Why this is not a mob_aura mode

Every other radius effect in the format runs on the horse’s own tick and looks outward. This one runs on somebody else’s event and looks inward, and folding it into mob_aura would put a global event handler behind a verb whose whole contract is “a beat, a radius, a cap”. Keeping it separate keeps that contract honest.

The gene that justifies the family

A player who has never cared about invisible loci understands this one immediately, and it is the strongest argument the behaviour family has for existing: a horse worth breeding for something that is not its coat and not its speed. It is also why the cap matters — the gene is at its best when it makes a camp safe, and at its worst when it makes the world safe.

Planned source: common/genetics/genes/HolyWardGene.java