Previously known as "Screw_SubAnomaly1".
Automatically despawns entities the moment they spawn! Based on JSON rules you write yourself.
Originally built to remove TheBrokenScript's SubAnomaly1, now a general-purpose entity filter!
Features
Rule-based removal. Each rule is a JSON file listing entities and the dimensions it applies to. Entities are discarded the instant they join the world.
Entities or tags. List specific entities (minecraft:creeper), entity tags (#minecraft:raiders), or both in the same rule.
Per-dimension or global. Leave dimensions empty and the rule applies everywhere. Fill it in and it only fires in those dimensions.
Drop-in rule files. Rules live in config/sym/rules/ (global) or <world>/serverconfig/sym_rules/ (per-world). Edit the JSON, run /sym reload, done. No restart.
In-game rule editor. /sym, /symrules open a GUI. Add, remove, rename, enable, disable, and validate rules without touching the filesystem.
Live validation. On load, entity IDs, tags, and dimensions are checked against the registry. Unknown entries get flagged with a "did you mean…?" suggestion based on edit distance (Levenshtein). Missing mod namespaces are reported separately.
Keep list. Exempt specific entities from removal entirely, regardless of what any rule says. Also skips named mobs and tamed animals during bulk purge.
Server-side sync. On multiplayer, rules are synced from server to client so the editor shows the real state. Edits are permission-gated (op level 2) and round-trip through the server.
Debug channels. Optional logging for removals, rule errors, validation, and reloads. Output goes to console, chat, and/or config/sym/debug.log, each toggled independently.
Commands
All require op level 2.
| Command | What it does |
|---|---|
/sym |
Open the rule editor (singleplayer / LAN only) |
/symrules |
Client-side alias for the editor (used for dedicated servers) |
/sym list |
List loaded rules |
/sym reload |
Re-read rule files and re-sync to clients |
/sym stats |
Rule and entity counts |
/sym validate |
Show validation warnings |
/sym debug |
Show or set debug channel state |
Requirements
- NeoForge for Minecraft 1.21.1, at least version 21.1.100
Example rule (also available in config/sym/rules/_example.json)
{
"_comment": "Copy this file and rename it. Delete the _comment fields if you want to.",
"_comment2": "Empty 'dimensions' list means the rule applies in ALL dimensions.",
"_comment3": "Tags like '#minecraft:raiders' are also supported.",
"entities": [
"minecraft:creeper",
"minecraft:skeleton",
"#minecraft:raiders"
],
"dimensions": [
"minecraft:overworld"
]
}
An empty dimensions list means the rule applies in every dimension. Rename the file to start with _ to disable a rule.
I don't like your mobs, so I went ahead and installed this mod.
Configure your rules fully in-game! No file explorer tinkering required, unless you want to create global rules.
If you don't want to use the in-game configurator (for whatever reason lol), just create your rules manually using this example file! Always auto-creates if it doesn't already exist.
Don't know what you're exactly looking for? Just type it out and use the auto-suggest feature! Feels just like typing a command in chat. Accent color of the UI is customizable too, as seen here! It's an aqua green instead of the original amber color. :P
Accidentally did the unforgivable and misspelled your mobs, tags or dimensions name? Don't worry, the Levenshtein algorythm will find the correct thing you were actually looking for! Wrong thing? Just press that "Edit" button and type it yourself!