HIGHLY WIP let me know if anything breaks or if you want features mostly focusing on the 1.21.1 version for now in terms of updates to the mod I might eventually update the 26.1.2 port:

Every world in Micro Mayhem has a microscopic ecosystem running underneath it. Bacteria, viruses, fungi, and parasites live on blocks, in water, in the air, on mobs, and inside the player. You cannot see them without tools. They do not wait for you to find them.

Each organism is procedurally generated from the world seed. No two worlds have the same strains. They mutate over time, compete with each other for territory inside hosts, form symbiotic relationships, respond to biome conditions, and evolve under pressure. A commensal strain you find on day one might be something entirely different by day thirty.

You interact with this system through a set of lab tools. Swabs collect samples from any surface, mob, or the air. Petri dishes culture what you find. A microscope reads out the full biological profile of whatever you are looking at. A centrifuge isolates individual strains from mixed samples. An irradiator accelerates mutation and lets you apply directional pressure toward specific traits. A gene splicer combines two strains into recombinant offspring, sometimes producing traits neither parent had.

Infections are modeled across four body systems: respiratory, digestive, skin, and circulatory. Each has its own colony space, local immunity, and health pool. Infections progress through five stages. Severe infections cause permanent damage. A neglected circulatory infection can kill you. A healthy microbiome of established beneficial strains resists pathogens before they ever take hold.

Every world contains one unique catastrophic strain. It is out there. Finding and characterising it is the closest thing the mod has to an endgame.

Tools also exist to protect yourself. A hazmat suit blocks all environmental transmission. Antibiotics, antivirals, antifungals, and antiparasitic drugs clear infections by type. Vaccines can be engineered from cultured strains. The suit has to be sterilized before you take it off, or whatever it absorbed comes with you.

This is a beta. The systems are functional and the simulation runs. Expect rough edges.

Micro Mayhem - Basic Usage
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SAMPLING
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Right-click a block surface with a Swab to collect a surface sample.
Right-click in open air to collect an airborne sample.
Right-click near a mob (within 3 blocks) to sample it.
One swab is consumed per sample. The rest of your stack stays sterile.

VIEWING
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Hold a contaminated Swab or ready Petri Dish and right-click the Microscope.
Results appear in chat. First view adds the strain to your Codex.

CULTURING
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Hold an empty Petri Dish with a contaminated Swab in your off-hand and right-click.
Culturing takes 20 seconds. Keep the dish in your inventory while it incubates.

COPYING A CULTURE
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Hold a ready Petri Dish in main hand, empty dish in off-hand, Nutrient Agar in inventory.
Right-click to copy. One Nutrient Agar consumed.

CENTRIFUGE
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Place the contaminated petri dish and two empty ones in the slots and it will produce separated samples.

IRRADIATOR
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Put glowstone dust as fuel.
Optionally add a pressure item to bias mutation direction.
Finally add the contaminated petri dish and empty petri dishes.

DIRECTED EVOLUTION (IRRADIATOR)

The Irradiator lets you push mutations toward specific traits by placing a pressure item in the bias slot alongside your culture.

Load a ready Petri Dish, then glowstone dust as fuel, then optionally a pressure item.

The cycle produces 4 mutant candidates. Pick the one you want. Autoclave the rest. Make copies with Nutrient Agar before irradiating so you never lose a good strain.

Pressure items and what they select for:

Blaze Rod Push toward Grade III virulence

Feather Reduce toward Grade I virulence

Sugar Bias toward beneficial effects

Rotten Flesh Bias toward harmful effects

Slime Ball Increase transmissibility

Chorus Fruit Add a new spread vector

Fermented Spider Eye Force wither/necrotic expression

Golden Apple Force regeneration/healing expression

Bone Meal Push toward commensal (no effect)

Amethyst Shard Stabilise the strain (slow future mutation rate)

Each pressure item applies with 80% probability per candidate. With no pressure item loaded the mutation is entirely random. Cycle duration scales with how genetically stable the strain is — freshly mutated unstable strains process faster than old established ones.

GENE SPLICER
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Place the contaminated petri dish A and B in the slots, as well as fill the other slots with empty petri dishes.

SYRINGE
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Hold syringe with a ready dish in off-hand and right-click to load.
Right-click a mob or player to inject. Right-click air to inject yourself.
Symptoms appear after a latent period, not instantly.

AUTOCLAVE
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Right-click holding a swab or petri dish to sterilize it.

Right click with empty hand to sterilize hazmat suit

HAZMAT SUIT
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Wear all four pieces to block all environmental and contact transmission.
Sterilize by right clicking autoclave empty handed to clean the suit before taking it off gives you 10 second grace period before it gets dirty again.
Contaminated pieces in your inventory will expose you if you are not wearing the full suit.

COMMANDS
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/microbiome See your active infections and body system health.
/immune See immune strength and autoimmune status.
/codex list Browse all discovered strains.
/straininfo <id> Full details on any strain by ID.

/codex Shows total number of strains discovered in your Codex.