The Hollow

A dread meter rises while the player is alone in the dark, and it bends what the player sees and hears. Once it reaches a threshold, the mod sends something after the player. A light source at level 13 or higher sends the darkness away at once, and a calm player lets dread fall below 55, at which point it loses interest. Nerve lasts about 90 seconds, which is roughly how long a player can outlast it before it is gone for good.

The Hollow is not a monster that hunts on a timer. The server recomputes its state twice per second and the client never guesses; it only reacts to what the server reports. Once the player is hunted, the darkness spawns 14 to 22 blocks away, deliberately preferring places that face the player. Its first sighting is always a surprise, and it obeys one rule: when the player looks at it, it stops dead, and when the player looks away, it walks closer. Hitting it deals no damage, and it only raises dread. It reaches the player but does not kill them.

The mod is built for Minecraft 26.2 with Fabric Loader 0.19.3 or newer and Fabric API 0.155.2 or newer. Servers that run it need every player to install it too. Files are published for 26.2 only, with 1.0.0 as the latest, and the mod is released under All rights reserved, so it is not open source.