From The Forest

Upon first playing the addon on a fresh world, you will not notice anything happen right away. This is because events will only begin to happen when the world is at least 60 minutes old, or after 3 in-game days. If your world is already 3+ in-game days old, then you will start noticing events right away.
 

When players are in forest biomes, "The Shifter" will lurk and hunt when the time is right, while using other tricks to catch players when they least expect it.

The Shifter will spawn mostly during the night, but can occasionally spawn during the day depending on different circumstances.

Important:

The addon is still in early stages and designs, sounds, and features may not be final.

The add-on also comes with 3 settings to choose from:

Normal Setting:
-default attack damage
-default health
-default spawn rate

Hard Setting:
-increased attack damage
-increased health
-increased spawn rate

Nightmare Setting:
-further increased attack damage from Hard Setting
-further increased health from Hard Setting
-further increased spawn rate from Hard Setting
-events will happen immediately when applying to a fresh world (no 3 in-game day or 60 minute wait)
-commonly spawns during the day
-spawns in any biome