General Changes (Global)
Universal Aggression: All hostile mobs are now permanently aggressive towards players.
Increased Speed: Most hostile mobs have had their base movement speed increased by 20%.
Extended Follow Range: The distance from which hostile mobs can detect and follow a player has been increased to 150 blocks.
Friendly Fire Prevention: Mobs will no longer attack each other, even if hit by a stray projectile from another mob.
Zombie
New Variants:
Giant Zombie: A larger, slower, and more powerful zombie with 60 health and 6 attack damage. It can break blocks and will launch players 10 blocks into the air upon hitting them. Spawns with a 2% chance.
Kamikaze Zombie: Spawns with TNT on its head. When close to a player, it will ignite and charge, exploding upon death. The explosion only damages players. Spawns with a 5% chance.
Pyromaniac Zombie: Spawns with a red banner on its head. It will set flammable blocks on fire as it moves. Spawns with a 10% chance.
AI & Behavior Changes:
Miner & Builder Zombies: Their AI has been improved to prevent them from getting stuck. They now move closer to blocks before breaking or placing them.
Builder Zombies: Now use full cobblestone blocks to build paths and pillar up.
Increased Speed: The speed at which they break and place blocks has been increased.
Removed Abilities:
Zombies no longer steal food or other items from the player's hotbar.
Skeleton
Equipment:
Armor: Skeletons now spawn with random pieces of armor, with a 5% chance to spawn with a full set of diamond armor.
Sun Protection: 20% of skeletons will spawn with a leather helmet, preventing them from burning in daylight.
Shields: 15% of skeletons will spawn with a shield and use it to block incoming attacks when a player is near.
Combat Enhancements:
Increased Fire Rate: Skeletons shoot 20% faster when a player is within 8 blocks.
Tipped Arrows: Arrows are now randomly tipped with Poison, Slowness, Weakness, or Mining Fatigue.
Attack Patterns: Skeletons have several new attack patterns: a rapid 3-shot volley, a powerful charged shot, and a wide group shot.
Advanced Targeting: They can now shoot through glass and lava, and will attempt to shoot predictive shots at jumping players.
Behavioral Changes:
Evasion: Skeletons will jump away from players who get too close and will retreat while shooting.
Provocation: They may shoot at other neutral mobs to provoke them into attacking the player.
TNT Targeting: They will shoot at any nearby active TNT.
Removed Abilities:
The "sand trap" ability has been removed.
Creeper
Spawning: 3% of creepers will now spawn as charged.
Explosion Mechanics:
Wall-Hacking: Creepers can now detect and begin to explode even through walls.
Player Pull: Just before exploding, they will pull the player towards them.
Enhanced Explosions: Explosions are more powerful, can break through walls, and leave behind a lingering potion cloud (Slowness or Weakness).
Special Explosions: There is a chance for explosions to create a crater of lava or water, throw blocks into the air, set the ground on fire, trigger a chain reaction of smaller explosions, or launch the player into the air.
Other Abilities:
Night Strength: Creepers gain a strength buff at night.
TNT Placement: They can now place and ignite TNT near players.
Mob Attraction: When swelling, they attract other nearby mobs to their target.
Removed Abilities:
Creepers no longer cause thunderstorms when spawning.
Enderman
Special Variants: Only 25% of Endermen will have special abilities (configurable).
Teleportation:
They teleport 50% more frequently.
They can teleport behind the player.
They can teleport other hostile mobs closer to the player.
They will teleport away 70% of the time when hit.
Block Interaction:
They can steal the block from directly under a player's feet.
They can place blocks in front of a running player to obstruct them.
They can build barricades to block the player's path.
Other Abilities:
Night Strength: Endermen gain a strength buff at night.
Rain Strength: They gain an even stronger damage boost during rain.
Item Manipulation: They can attract nearby items and swap items in the player's hotbar.
TNT Teleport: They can teleport active TNT to the player's location.
Removed Abilities:
Endermen no longer teleport other mobs directly to the player.
Spider
General:
Spiders are now always aggressive, regardless of the time of day.
They receive a speed boost at night and a speed/strength boost in the rain.
New Abilities:
Web Attacks: They can shoot webs at players or create a web network around them.
Minion Spawning: They can periodically spawn Cave Spiders.
Teleportation: They have a chance to teleport.
Environmental Traps: They can place web traps on the ground and web doors shut.
Ceiling Spiders: 20% of spiders will spawn as "ceiling spiders" that cling to ceilings and drop down on players. They can also break blocks above them to reach players.
On-Hit Effects: When a spider attacks, it will inflict Nausea, a brief paralysis (extreme Slowness), and will throw the player into the air.
Witch
Combat:
Potion Arsenal: Witches now use a wider variety of potions, including strong harming, poison, and weakness, as well as lingering potions. They can also create a "chaos zone" by throwing multiple potions at once.
Ally Support: They will heal and strengthen other nearby mobs.
Other Abilities:
Minion Spawning: They can summon baby zombies, skeletons, and cave spiders.
Invisibility: They have a chance to turn invisible.
Rain Strength: They gain a damage boost during rain.
Removed Abilities:
Witches can no longer teleport the player.
Phantom
General: Phantoms now have increased flying speed.
New Abilities:
Air Vortex: They can create a vortex that slows the player.
Minion Spawning: They can summon smaller "mini-phantoms".
Teleportation: They have a chance to teleport.
Block Piercing: Their attacks can now go through blocks.
On-Hit Effects: When a phantom attacks, it will launch the player into the air.
Nether Mobs
Ghast: Shoots fireballs three times more frequently.
Piglin & Piglin Brute: Are now 1.5x faster and will always be hostile to players, regardless of gold armor.
Other Mobs
Iron Golem: Will now attack players on sight and will launch them high into the air on hit.
Ravager: Can now break most blocks (except for highly resistant ones like obsidian and bedrock) to get to its target.
Cow: When a player attacks a cow, that cow and all others nearby will become hostile towards the player for two minutes.
Squid: Will now reflect double the damage back to any player that attacks it.
Raids
Reinforcements: For every raider that spawns naturally during a raid, an additional one will spawn nearby, effectively doubling the size of the raid.

Nightmare Mobs HardCore