How to Host a Parasites 100 Days Server (Forge 1.12.2 Guide)
Parasites 100 Days is OkRobert's post-nuclear hardcore survival pack built around the YouTube series of the same name — parasitic creatures overrun the world and you have to gather resources, build defenses, and fight back against swarms that only get worse. It runs on Forge 1.12.2, and because the whole point is surviving a punishing 100-day countdown, a clean first boot and a RAM floor sized for the pack's mob load matter more than usual. Here's how to get a Parasites 100 Days server running correctly from day one.
Start with at least 5 GB of RAM. Parasites 100 Days runs on Forge 1.12.2 with a dense mod list built to simulate relentless parasite swarms across a post-nuclear world, and 5 GB is the pack's own recommended floor for keeping tick rate stable once the infestation starts escalating.
Import the modpack through a dedicated server panel instead of guessing from a client export. A clean import pulls the exact Forge 1.12.2 version and the exact mod jars the pack was built on — OkRobert's pack pins specific mod versions, and a mismatched jar is one of the fastest ways to get a boot-time crash.
Watch the console through the full first boot before touching anything else. Forge 1.12.2 packs with custom mob AI, like the parasite swarms here, can take several minutes to register entities and generate structures — you want to see the server reach "Done" with no repeating Forge errors before you consider it ready.
Only invite your group after you've confirmed one full clean boot and a short solo test. Parasites get more aggressive the longer the world runs, so you want spawn rules and world generation confirmed stable before people start building the defenses they'll be relying on for the full 100-day run.
Back up the world before any loader update, modpack update, or config change. Losing a Parasites 100 Days world means losing the exact day count and defense progress the entire run is built around, and a pack this punishing doesn't give you a second chance if a bad restore wipes your base.
Use a cleaner Parasites 100 Days path
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