Magic on death

Crossing two of them

What it does

That last row is not a shrug. The three variants are answers to one question — what happens here — and a horse carrying two of them is asking for two contradictory things. Rather than pick a winner, the locus says the pair is silent.

No feral horse explodes

This is the one locus in the mod whose founder table is carriers only. Wild horses carry the alleles — a few percent each — and no wild horse is ever born with two of anything, so a feral animal can never crater the ground it dies on.

Every other magical gene here does the opposite, and deliberately: a locus whose carrier is invisible puts its expressing combinations in the wild, so that what you catch is what you watched it do. This one is a hazard rather than a prize, and a horse that leaves a crater has to be somebody’s fault.

Health

None while alive. A volatile horse is an ordinary horse right up until it stops being one, and it is worth knowing that the explosion is a mob explosion — whatever killed it, and whatever was standing nearby, is inside the radius.

Its gene carrot

Gene key

horsegenetics.magic_on_death

Alleles

Lav lava spring, Wat water spring, Xpl volatile, n

Priority

134 — the magical utility band, beside milk

Reaches the game as

an on_death effect

Coat effect

none, ever

Why the ground and the drops are two verbs

Because they are two questions with two answers, and folding them into one would make “explodes and drops diamonds” impossible to express as the two independent loci it is. As two verbs on two genes it is a cross; as one table it would have been a row somebody had to remember to write.

They are nonetheless handled in one translator class, because they share exactly one thing — the moment — and nothing else, including which event they can run on. LivingDropsEvent can rewrite the drop list and cannot usefully place a block; LivingDeathEvent is the other way round.

The fluids only fill a free block

A lava or water source is placed only into air, or into something a fluid would wash away anyway. The alternative reading — replace whatever is there — turns a novelty locus into a griefing tool that nobody can see coming, since the carrier looks like any other horse.

var existing = level.getBlockState(at);
if (existing.isAir() || existing.canBeReplaced()
        || existing.getFluidState().getType() != Fluids.EMPTY) {
    level.setBlockAndUpdate(at, state);
}

Nothing here fires in the read-only gallery dimension, for the same reason the glow light block and the ground spread do not: a debug pen is for looking at horses, and a horse that craters one is a bug report about the debug pen.

The exception that proves the founder rule

The standing rule for a magical locus with an invisible carrier is that the wild population sits on the combinations that show. The argument is a good one: once a carrier is invisible, a founder population full of carriers is a locus run in the dark — you cannot see what a horse has, so you cannot choose what to pair it with, and every result is an accident.

That argument assumes the outcome is something you would want to find. Here it is not. A wild population of exploding horses would mean a player who has never heard of this gene loses a stable to it, and the discovery would be an accident in the bad direction. So this locus runs the health loci’s rule instead — carriers only, never affected — and the interesting horse is one you assembled from two ordinary-looking parents.

The useful one

Water is on the same locus as lava and the explosion, which makes the whole thing a gamble worth taking: three recessives sharing a locus means a breeder chasing an infinite water source is also breeding, in the same herd, something that will eventually go off.