Ialie and her cluster have spent generations in an ancient abandoned Dwarven temple. The magic in the temple has seeped into the spiders and over time has caused the carapace to fuse with the ore surrounding the buried temple. Now the giant spider is able to reflect almost any magic that targets them.

Description.
Formed from the experiments of mages long past these giant spiders have been infused with a mineral known as aechronite. Being able to reflect all magic directly targeted at them has confused and defeated many that have confronted them over the centuries. Those who lived to tell the tale have been passing the false rumor that the spiders are powerful magic users hoarding an untold amount of weapons and coins.
Ialie and her cluster want to be left alone with no interference from humanoids. They will attack any who threaten harm or encroach too far into their territory.
Adventure Hook. An old rumor says there’s a giant spider in the mountain with the hardest hide known in the land. Cliste the Blacksmith has a reward of 300 gp for a full Arcane Giant Spider exoskeleton.
Combat.
Ialie will first attempt to put as many opponents to sleep with her ‘Slumber’ ability. Then she will restrain the nearest opponent so she can poison and paralyze them. If any of her brood are threatened she can use the ‘Now You See Me’ ability to quickly cross the battlefield. Their immediate goal is protecting and feeding the cluster of arcane spiders. Once bloodied she will bite as many foes as she can before escaping with her brood deeper into the nest.
History.
With a History or Nature check, characters can learn the following:
DC 10 The carapace looks similar to the unique mineral that the mountain is known for (aechronite).
DC 15 The carapace and the unique mineral are known to reflect any magic that directly targets it.
DC 20 Ialie and her cluster were the results of an experiment in ancient history that fused the aechronite with the exoskeletons of various monstrosities.
Behavior.
- Attacks on sight
- Lounging in the web
- Expanding the web area
- Demand surrender, tribute, or retreat
Signs.
- Giant spider webs growing in frequency
- Spider web cocoons of various sizes
- Sparkly obsidian ore that reflects magic called aechronite
- A loud purring or scratching sound that grows louder and then suddenly stops
Harvesting.
DC 10 – Spider Venom – The venom of this giant spider causes powerful paralysis when ingested. Use: Can be used to coat up to 10 pieces of slashing or piercing ammunition, or two slashing or piercing weapons. Applying the poison takes an action. A creature hit by the poisoned weapon or ammunition must make a DC 11 Constitution saving throw, taking 9 (2d8) poison damage on a failed save, or half as much damage on a successful one. If the poison damage reduces the target to 0 hit points, the target is stable but poisoned for 1 hour, even after regaining hit points, and is paralyzed while poisoned in this way. Once applied, the poison retains potency for 1 hour. Value: 30 gp.
DC 15 – Spider Fangs – The large fang of the giant spider is a little too unwieldy to use as an actual weapon. They do however make fantastic ceremonial daggers and are used in dark magic rituals. Value: 16 gp.
DC 20 – Spider Carapace – The aechronite chitin of this giant spider is what gives it the anti-magic properties. When smelted it becomes an almost impenetrable barrier against both weapons and magic. Value: 300 gp. Crafting: +1 medium or heavy armor with the Reflective Carapace feature.
Sources of Inspiration
Matt Colville’s Action-Oriented Monsters – https://www.youtube.com/watch?v=y_zl8WWaSyI
Legendary Bestiary: Legendary Actions for Low-Level Monsters – https://www.drivethrurpg.com/product/307926/Legendary-Bestiary-Legendary-Actions-for-LowLevel-Monsters
LevelUp 5e Monstrous Menagerie – https://enpublishingrpg.com/collections/level-up-advanced-5th-edition-a5e/products/level-up-monstrous-menagerie-a5e?variant=41366519775426
Hamund’s Harvesting Handbook: A Complete Guide to Harvesting and Crafting in D&D 5e – https://www.dmsguild.com/product/276213/Hamunds-Harvesting-Handbook-A-Complete-Guide-to-Harvesting-and-Crafting-in-DD-5e
Drop your requests for ttrpg homebrew magic items, monsters, or random tables in the comments below.