Hello again! So sorry about the recent inactivity. I've been very busy, but hopefully I should be able to upload more content a little more frequently now. Today's command creation is Spooky Halloween Monsters in One Command! Let's get this started!

What does this command creation add?
It adds nine new variants to currently existing mobs as well as one challenging battle! These range from hordes to swordsmen. Here's the list of everything and what they drop:

• The Withering Skeleton: An over world wither skeleton that can drop Withering Skulls. These skulls can be used to spawn the battle mentioned further in this post.
  
  
• The Soul Thief: A skeleton that steals souls with its scythe, the Soul Thief has two drops. It can drop the Mysterious Jack o'Lantern, an item required in spawning the battle, and also the Skeleton's Scythe, which has no particular use except as an unbreakable treasure.
  
  
• Poisoned Spider: A cave spider that spawns during Halloween. Regular poison splash potions can be dropped by the spider, which could prove useful in some situations.
  
  
• The Undead Chaser: It is a scary fast monster, who can swim quickly, run on water, and takes little fall damage. You'd better have a plan before fighting these creatures, or else you'll be quickly taken out. They can drop their boots, but very rarely.
  
  
• Zombie Horde: A group of four zombies that can spawn. They have no special drops, but they are still a matter not to be messed with!
  
  
• The Undead Swordsmen: A zombie riding a zombie horse? How much worse could it get? The Undead Swordsmen can drop its Blade, but other than that, there isn't anything else to know about its drops.
  
  

The following monsters will only naturally spawn in the nether.

• The Massive Magma Cube: A large magma cube that can drop 0-4 magma creams as well as possibly a nether wart from the initial magma cube. Be careful around them because they deal massive amounts of damage while also being very massive.
  
  
• The Blaze Horde: A naturally spawning bunch o'blazes. Don't be deceived by their lack of numbers, for they will easily take care of disruptions if you aren't careful about approaching these menaces.
  
  
• The Golden Pig: A stronger, richer zombie pigman. They are just as dangerous as regular pigman, especially since their bling will easily distract attackers.
  
  

Drops and Chances:
Here's a complete list of all Halloween monster drops.

• Withering Skulls: 50% chance to be dropped by Withering Skeletons.
  
  
• Mysterious Jack o'Lantern: 30% chance to be dropped by Soul Thieves.
  
  
• Skeleton's Scythe: 1% chance to be dropped by Soul Thieves.
  
  
• Regular Splash Poison Potion: 5% chance to be dropped by Poisoned Spiders.
  
  
• Chaser's Boots: 1% chance to be dropped by Undead Chasers. (iron boots with Feather Falling IV, Depth Strider II, and Frost Walker II)
  
  
• Swordsman's Blade: 30% chance to be dropped by Undead Swordsmen with full durability.
  
  
• Netherwarts: 25% chance to be dropped by Massive Magma Cubes.
  
  

*All other drops are either common or not necessary to know the chances of being dropped.

Spawning the Battle:
Throw three Withering Skulls and four Mysterious Jack o'Lanterns on the ground (on the same block of course) and the battle will commence! I bid thee good luck!

Why can't I find monsters?
This command creation will only work if your computer's date is October 31st (Halloween). If it isn't that day, it will not spawn the monsters. You can set your computer to that date, then restart Minecraft. It should then work properly.

How does this work?
For all you who are curious, this relies on the fact that some monsters have a chance of spawning with a pumpkin or jack o'lantern on their heads on Halloween. The commands will detect that pumpkin/jack o'lantern and will replace that mob with a random variant monster.

Get the Command:

• 1.12: https://pastebin.com/0SUHuruh
  
  

Credits:

• Made by ClassyElm
  
  
• Used MrGaretto's Command Combiner