ExtremeCore

The mod changes mob behavior and world rules. Zombies learn to break blocks and can hide behind them, and they apply Slowness II to players standing near them. Skeletons receive 200% more health and a larger follow range, and their arrows apply Weakness. Endermen become angrier and paralyze players who catch their gaze for a short time. Creepers are always charged, and Drowned spawn with a trident every time. Bats turn into dangerous attackers that deal 1 HP of damage, even to dolphins that were turned hostile.

Other changes affect the world itself. Days last about a third of their former length, underwater air bubbles are reduced by 5, and Ghast fireballs can no longer be deflected. Mobs ignore boats and minecarts entirely. Iron Golems stop dropping iron, and Villagers refuse to trade. Chests inside structures are left empty or stripped of useful loot.

Because the changes live on the server, players join without installing anything. The mod is published for Forge only, with its latest file being 0.5.1 for 1.20.1, released 2026-07-11 on the beta channel. It is released under the MIT License and is not open source.