Damien Eltzwright

Damien moves between states as the situation changes, reacting to how far away the player is, whether the player can see it, the light level and some randomness. In the watching state it observes a player from 20 to 40 blocks away in darkness, keeping out of line of sight and finding cover when spotted. In the stalking state it follows silently behind footsteps, opens and closes doors, and can steal items from the hotbar or drop them nearby. A later imitating phase copies the behavior of passive animals as a disguise, and the mimic learns over time.

Damien also scans the player's buildings and can teleport them into a corrupted mirror copy built with twisted blocks. When the mega form is reached, Damien is pulled toward the player by velocity, paths to them and destroys blocks in progressive stages. Its attacks hit four times per second for 8 damage each, and once it transitions it stays until it despawns. A Hard Mode setting makes Damien more active, and the entity is especially active at night.

The mod requires Geckolib. Installation covers the server and each player's game. Files are published for Forge only, for Minecraft 1.20.1, and the license is Creative Commons Attribution Non Commercial 4.0, which means the mod is not open source.