From The Fog Data Pack vs Mod

Choosing Between the Data Pack and the Mod

The From The Fog haunting is distributed in two forms, and the difference matters for how you install and run it.

The data pack is a world-level addition. You drop it into a world's data pack folder, and it applies to that world only. It uses the game's built-in data pack systems, so it works on a vanilla server or single-player world without any loader. If you want the haunting on one specific world and nothing else, this is the lighter option.

The mod form is loaded through a mod loader and applies wherever that loader runs. It can bundle behavior a data pack cannot easily express, and it is the version to pick if you already run other mods alongside it.

Functionally, both deliver the same haunting: the signs Herobrine leaves and the escalating danger over time. Pick based on whether you want a per-world install or a loader-wide one.