Magical gene / no coat effect

Hot blooded

Snow will not lie near it and ice does not last. A hot-blooded horse leaves a thawed circle wherever it stands, which is charming in a paddock and a genuine nuisance on a frozen lake.

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
Hot/Hotmelts snow and ice within a short radius
anything elsenothing

On a frozen lake

It melts the ice it is standing on, and then it is in the water. This is funny rather than broken, and it is the reason a hot-blooded horse is a liability in exactly one biome.

Health

None directly — but see above, and note that it does not make the horse immune to anything cold.

Gene key
horsegenetics.hot_blooded
Alleles
Hot hot-blooded, n
Inheritance
homozygous recessive
Reaches the game as
a spread effect with a melting cover word
Coat effect
none, ever
Melting ice makes flowing water, and flowing water is a known tick cost

Worse, in a snowy biome the snow re-forms and is melted again — a permanent melt/refreeze loop under any stabled horse, running for as long as the chunk is loaded. Cap the rate hard, and consider melting to air rather than to water. This is the highest ongoing cost of any spread gene.

Do not eat placed blocks

The spread verb takes a vocabulary word rather than a block id precisely so the judgement about what may be converted stays with the translator that knows the game’s blocks. Packed ice and blue ice in a build are somebody’s floor.

One new vocabulary word

No new verb. spread already converts ground within a radius on a beat with a probability; this adds a word to its vocabulary the way dryad does. Two genes, two words, one existing machine.

A gene that edits the world

Only two loci in this batch change blocks rather than entities, and both are spread. That is a deliberately small category: a gene that rewrites terrain is the kind that gets a mod uninstalled, and keeping the world-editing surface to one verb with a closed vocabulary is what makes it safe to have at all.

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