Mutant Beasts Add-on 1.17+

Mutant Beasts was so ahead of its time with some out-of-mind Massive Creatures added to the game, they don't stray far away from vanilla since they're all just an empowerment of the already existent mobs for instance: Zombies/ Endermans/ Creepers...

The creatures don't spawn naturally in your world, you need to brew a certain potion called "Chemical X", only then you can summon the beasts by throwing the brewed potion at a particular mob (Keep in mind not all mobs are able to upgrade), but before doing this take into account that all the mutant creatures are extremely strong and won't show you any mercy whatsoever, with that being said take your precautions!

this mod is easily the best mutant creature out there even after years, it still holds the crown.