A Green Dragon Handing Out Headbands Of Intellect... For A Price.

TL;DR: A dragon (Green) creates a set of Headbands of Intellect with a catch: the owners of these items must do whatever she asks or lose their (19 int) smarts. Creatures of 'low' intelligence (less than 8 int score) are the easiest targets and long-term victims.

Contents:

1/ The Grand Green Lady herself / green dragon

2/ The Coil of Brilliance / magic item

3/ Typical Targets to Turn Tricky (and not want to go back to being 'stupid') / NPC set

1/ The Origin Story: The Great Green Lady

A very long time ago a slain Great & Very Olde Mommy Dragon left behind a horde for her children. Actually, the horde was already partially looted (these heroes and adventurers were making several trips… hey, gold is heavy) and the quick and clever dragonlings took whatever they could. Turns out the adventurer guarding the loot wasn't that clever after all. The smallest of the baby green dragons gets an apparently useless Tome of Clear Thought (already used / blank). No one knew this at that time but the writing in these tomes comes back every 100 years, giving the reader two (2) intelligence points each time this happens. True, for most shorter-lived creatures this is a one-shot book - but this really works amazingly well for dragons (and liches… but that is another story which shall be told at another time).

Down through the centuries this dragon ends up being rather smart. Terrifyingly so, actually.

Long before she is even Ancient, she has more intelligence than anything, including most illithid brain pools, aboleth mind-gatherings or even the gods of knowledge. She realizes that knowledge is power, sure - but being able to control who gets knowledge is ABSOLUTE power. With the combination of her intelligence, magical ability and the capacities of her servants she makes the Coil of Brilliance:

2/ Eternal Coil of Brilliance

This device gives 19 intelligence to whomever is connected & attuned to part of it, identical to the Headband of Intellect. This silver rune-encrusted coil can break off at any point, giving 'parts' that can re-attach if so desired. The detached loop changes shape enough that it can be worn as a ring, headband, nose ring, toe ring, belt, ankle bracelet, necklace, cloak pin or virtually anywhere else a loop (of any size you like) can fit. After one hour ('short rest') one's attunement kicks in and the intelligence of the user rises to supra-genius levels - and does not vanish unless the attunement is broken.

Curse: This item contains sentience and can speak to anyone who is connected to a part of this Coil. It requires any user attuned to this device to obey - lest the attunement is severed and the vast intelligence vanish.

3/ A Motley Crew of NPCs

The DMG R.A.W. 'Headband of Intellect' does not seem to require a minimum intelligence. This means that The Great Green Lady has a vast repertoire of otherwise-dim creatures under her power:

• Greatworm Smoogg Naming herself (incorrectly) after the legendary dragon Smaug, this Purple Worm has become the leader of Green Lady's not-so-secret underground spy forces. This all started when this colossal worm ate a particularly tasty & chewy adventurer and Smoogg ended up getting a Circlet of Brilliance stuck between her teeth (it has since wrapped around that tooth securely and would be hard to remove without killing its owner first). Knowing very little about dentistry, this worm has been reluctant to do what it does best (laying down rapid tunnels for the rest of the underground spy group) as it does not want to dislodge this magic item and go back to being one of the most stupid creatures alive.

Still, The Greatworm Smoogg does do the Green Lady's bidding and has been more than foundational for setting up a vast and wide network of tunnels, resource logistics, planning and, of course, spying.

• Kindly Ogre 'Sickbane' Sogramire This ogre originally tried this rune-encrusted nose ring on as a joke with some of his peers. Since then, the ogre has abandoned his lesser-intelligent ilk. He got hired at a nearby town and discovered the joy of organizing the town guard. He loves this job for many reasons: not only does regular combat come to him, he has been granted armour, weapons and backup archers to virtually guarantee he survives any situation he plans for. Though unwise, he has learned Ritual Caster from the Green Lady and has made himself indispensable as a caster of spells up to 3rd level.
• A skeleton found one. Now he is brilliant but oh so fragile. He (she?) is the most cowardly un-creature known as it is deeply concerned about his or her mortality, possibly ironically. (S)he wants to do many things before it dies including getting a fleshed out body again. But what happens? When the soul comes back will he or she lose their mind? Will they blend? Will she even be alive or just become something like a… ghoul? No idea. The tough part: adventuring as a skeletal coward long enough to afford the Resurrection
• a very young wyrmling White was given one. Imagine realizing just how utterly stupid your peers are! Horrid. And having to serve a Green! Worse.
• What happens to a Gibbering Mouther that is an ultra smart genius? What does it do with all the combined bits of its fragmented mind? No idea. But i still try to think about it as a DM until it hurts and i have to lie down for a bit.
• The Mimic as overly contemplative furniture is also adorable, another favourite character here. It would also make a rather terrifying librarian.
• As a DM you can put one of these on any PC, NPC or monster that is not so clever and have a riot. I have more but i want to get this off my computer screen (it has been sitting 'on deck' here for days). I can modify this later if anyone likes it - please let me know! I was going to make this longer… but i have too many other ideas i want to play with.

Please steal this idea and let me know if it was any fun at all. If you are inspired, i am thankful beyond words. Letting me know your story is all the thanks i would ever need.