Immortuos Calyx

Immortuos Calyx

Adds a parasite that consumes players and other entities from the inside, gaining control over their motor functions. Loosely based off of the Velonaceps Calyx parasite from Barotrauma.

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2.4K Downloads
fabricforgeneoforgegame-mechanicsmobs
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Screenshots

Infected Player
Rusk Co Research Facility
Genetic Researcher

About this Mod

Spooky jam 2020 entry

We've been getting reports of players infected by a strange new disease. Days after infection we've seen strange, aggressive behaviors from them. After further inspection we found it is a parasite. Now named Immortuos Calyx, it poses a high threat to our way of life. We have developed a cure... but it's imperfect, and we can not risk distribution at this time. Stay safe, cook your food, and avoid infected individuals at all costs.

The shorthand explanation

Immortuos Calyx is a parasite loosely based off of the Velonaceps Calyx parasite from Barotrauma. The Immortuos Calyx parasite slowly infects an entity over time, ingraining itself in the host's organs, and providing all sorts of trouble (and in certain conditions, benefits!)

It also adapts the Gene system from Barotrauma into the mod as well, allowing for genetic implants to benefit the user, including slowing down or entirely stopping the progression of the infection.

Interested? Here's some more!

We recommend Patchouli, if you don't want to figure the mod out yourself, as a guide book for the mod has been written

This mod adds a couple of uncommon, infected entities, one that'll spawn in the sea, and one that'll spawn on land. Getting hit by one of these entities, or consuming their drops can lead to infection.

If the parasite consumes the player, or the player dies at a high enough infection level, an infected human entity bearing their name and skin may appear.

The infection has plenty of downsides, but some benefits too. Downsides especially for those living in warm environments, and benefits for those living in cold environments. Including modifying the speed, strength, and damage intake of the user, as well as preventing drowning, after a while.

We also introduce the Rusk Co. Research Facility, a village building that includes a Gene Encoder for genetic research, which also acts a new POI for the Genetic Researcher, a new villager type.

This village building is the gateway into the Genetic system, where you can implant genes from other mobs and entities to empower yourself. Patience however may be required, as vials can be contaminated. While a contaminated sample is still usable, it will bring downsides with it.

Server Hosting

Available Versions

Immortuos Calyx 2.2.1release
MC 1.21.1fabric
January 10, 2026
Immortuos Calyx 2.2.1release
MC 1.21.1neoforge
January 10, 2026
Immortuos Calyx 2.2.0release
MC 1.21.1neoforge
June 7, 2025
Immortuos Calyx 2.2.0release
MC 1.21.1fabric
June 7, 2025
Immortuos Calyx 2.1.0release
MC 1.21.1neoforge
May 26, 2025

How to Install Immortuos Calyx on Your Server

1

Order Server

Order a Minecraft Java server with at least 3 GB RAM (4 GB recommended).

2

Set fabric Loader

In the panel under "Egg", select the fabric loader and matching Minecraft version (1.21.1).

3

Install Mod

Open the mod browser in the dashboard and search for "Immortuos Calyx". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.

Compatibility

Mod Loaders

fabricforgeneoforge

Minecraft Versions

1.21.1, 1.19.2

Server-side

Required

Recommended RAM

4 GB(min. 3 GB)

Frequently Asked Questions

Immortuos Calyx server crashes on startup – what to do?

Most common cause: wrong fabric version or insufficient RAM. Check the server log (latest.log) for "OutOfMemoryError" or "Mixin" errors. With Mado Hosting: ensure at least 3 GB RAM is allocated and the loader matches the mod version (1.21.1). You can switch loaders with one click in the panel.

Is Immortuos Calyx compatible with fabric and forge and neoforge?

Immortuos Calyx officially supports fabric, forge, neoforge for Minecraft 1.21.1, 1.19.2. Note: Forge and Fabric mods are NOT cross-compatible – pick one loader and stick with it. The Mado dashboard automatically detects incompatible loader combinations.

Server lagging with Immortuos Calyx – how to optimize performance?

Recommended RAM: 4 GB (per 8 players). Use /spark profiler to check if Immortuos Calyx consumes the most tick time. Common fixes: reduce server view-distance to 8-10, install "performant" or "starlight" as supplementary mods on Forge. With Mado Hosting, your server runs on NVMe SSDs with dedicated CPU cores for minimal latency.

Rent Modded Server

Install Immortuos Calyx with just one click on your server.

Recommended RAM
4 GBab €8/mo
Min. 3 GB | +1 GB pro 8 Spieler
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NVMe SSD Storage
DDoS Protection included

Details

License
MIT License
Server-side
Required

Supported Versions

1.21.11.19.2