Statistics:

This Addon will make you Miserable Forever with Diablo Style Mobs Modifications!

Now the Mobs will be Much Harder to Defeat because:
♦ Their Speed Increases which is Hard To Hit
♦ Deadly Damage that can Kill with Just A Few Hits
♦ And Thick Health that is Almost Endless
They have Ranks that Show their Difficulty Levels:
♦ Rare
♦ Ultra
♦ Infernal

Examples:

Higher Rank = More Increase their Statistics

And they are So Annoying
We are Killed By Them Immediately while they are Almost Impossible to Kill By Us  (╥﹏╥)

For now, only the Most Common Mobs can be Modified such as:
Zombie, Skeleton, Spider & Creeper
More Mobs Coming Soon... (≧▽≦)

Spawn Chances:

Maybe I'm Exaggerating Too Much
I'm just trying to Scare You...Hee~Hee... (ΩДΩ)

Don't Worry, Modified Mobs are Rarely Found depending on their Rank:
♦ Normal Mobs = 380% Spawn chance
♦ Rare = 20% Spawn chance
♦ Ultra = 10% Spawn chance
♦ Infernal = 5% Spawn chance

But although their Spawn Chances are Very Small
Sometimes they Spawn More Often
so Be Careful when Adventuring
Usually they will Jumpscare You! (ΩДΩ)

Special Abilities:

Like in Diablo, they have Special Abilities like:

Blastoff = Throws Enemy in the air

Bullwark = 60% Damage Resistance

Cloaking = Completely Invisible

Darkness = Blinding the Enemy

Ender & Ninja = Teleport

Poisonous = Poisoning the Enemy

Quicksand = Slows the Enemy

Sapper = Hungry the Enemy

Sprint = Move Fast

Weakness = Weakens the Enemy

Wither = Wither the Enemy

Higher Rank = More Increase their Special Abilities

Identifiers:

When they Spawn, the Boss Bar & Colored Writings
Will Appear within Certain Distances according to their Rank:
♦ Rare = Blue in 10 Blocks
♦ Ultra = Yellow in 20 Blocks
♦ Infernal = Purple in 30 Blocks

Colored Particles also Surround them, so their Rank will be Recognized from Afar:
♦ Rare = Blue
♦ Ultra = Yellow
♦ Infernal = Bright Red, I Can't Find Purple  (╥﹏╥)

Each Special Ability has Different Identifiers, Examples:

Loots:

I Know if You Kill Them just Because you Want their Loots, right?

I Make Sure Your Effort will Pay Off because they will Drops:
♦ Double [2X] Loot of Ordinary Mobs
♦ Quadruple [4X] Exp
♦ And Random Enchanted Weapons / Tools:
♦ Rare = Iron
♦ Ultra = Golden
♦ Infernal = Diamond 

Examples:

Sometimes they drop 1-3 Iron Ingots / Gold Ingots / Diamonds, instead of Random Enchanted Weapons / Tools

Higher Rank = Better & Double the Loots

Don't Say that there are Still Not Pay Off, You are Greedy! (눈_눈)

Notes:

♦ There are Enderman & More Special Abilities, but have been Removed due to Causing Game Crash!  (╥﹏╥) [After All, it would be Too OP]

♦ Only Holiday Creator Features that Must Be Enabled!

♦ For Now, Only English Available

♦ Recommended playing this Addon in Version 1.17.0+

♦ Known Bug = Sometimes Identifiers Don't Appear & I Can't Fix It! [Minecraft Bug]  (╥﹏╥)

♦ Actually this Addon Based on a Java Mod named "Infernal Mobs" Made by Atomicstryker 

I Got Permission & It was Written on the Licence that:

♦ You are Allowed to Read & Use the Provided Sourcecode in order to Make Interacting Mods so long the resulting Mods Still Require My Originals to Function

♦ You are Allowed to Integrate Ideas / Techniques from My Sourcecode into your Mods & Sourcecode Assumed from Other Authors Fall Under their Respective Licenses & Copyright Statements

♦ A Link should Always be Provided

♦ All My Work is Open Source

Conclusion = I'm Allowed to Take Over This Addon with My Own Copyright As Long As I Link to His Mod! (≧▽≦)

Actually there's No Point in Posting the Proof above
Just in Case you Don't Believe it! 
(눈_눈)

And We Misunderstand Each Other during Conversation!

(≧▽≦)