Grandmother's Hexing Tooth, A System-Agnostic Magic Item

 Grandmother's Hexing Tooth

"Tales about the entity known most often as Grandmother are dark ones.  Her true nature is unclear to scholars, but she is commonly held to be either:

• the Queen of the Hags
• an arch-fey so mighty that the Courts of the Seelie and Unseelie are beneath her notice
• a devil from the Final Pit itself
• the embodiment of the most brutal side of nature incarnate. 

 Countless generations of parents have used her name to cow unruly children into a semblance of good behavior, the crowns of numberless kings decorate her lair, and every culture has a myth of her devouring some bold hero who set out to end her seemingly eternal evil.

And yet she is also portrayed as a whimsical creature, one who revels in causing chaos and confusion as much as actual harm.  Grandmother seems to enjoy defying expectations, rewarding those who amuse her with both cleverness and foolishness.  Her gifts are often invitations to disaster, but she seems equally pleased when someone manages to turn them to serve a good cause as when they result in doom.

This inherently paradoxical behavior is perhaps best seen in the many tales that cast her in the role of a Tooth Fairy - albeit with a dark twist.  You'll get no bright penny beneath your pillow from Grandmother.  She offers a replacement for your loss instead."   

Description:  A sharp triangular fang of black iron, shaped like a shark's tooth.  Radiates a magical aura of malice so strong even mundane creatures feel uneasy in its presence.  Prying into its nature with identification spells risks attracting the attention of its original owner.

Powers:  To use this item, a character must remove one of their own front or incisor teeth (or already be missing one) and jab the hexing tooth into their gums in the gap.  It will magically resize and bond to fit the void, although it remains glaringly obvious as a sharp, metal tooth.

Once every three days, the user may lay a curse on a creature within earshot simply by pronouncing its doom.  The curse causes random stabbing pains and generalized terrible luck that apply a 25% failure rate on attacks, skill tests, attribute tests, saving throws, active defense attempts (if your system uses parry rolls, for ex), or anything similar that uses a die roll to resolve success or failure.  Check by rolling a d20 each time a roll would succeed and if the result is 1-5, the result is a failure instead.  The curse will last 1d6 days.  Removing it earlier should require a lengthy (at least a day) and difficult magical ritual, or spells designed specifically to remove curses of near-deific power.  The user cannot predict the duration of the curse, nor can they control when it ends.  

Possible Origins:  It's an actual tooth from a shadowy semi-mythological figure that features in far too many cultures' legends for comfort.  She ripped it from her mouth full of iron fangs just so she could give it to you as a present.  Say "thank you" to your Grandmother.  

Complications:  You've attracted the attention of Grandmother if she gave this to you herself.  Alternately, you're one of many people who've crossed paths with someone that killed for that tooth.  That attracts her attention too.  Expect a visit at some point.  She enjoys visiting people.  

The tooth won't come out once you've jammed it in, at least not while you're still alive.  If you don't implant it, a remarkable series of coincidences will lead some ill-intentioned types to try to take it from you within a few days.  You could just let them have it, I suppose.  Nothing bad could come of that.

Grandmother likes her presents to get used.  If you go a week without cursing anyone using the tooth it will pick someone to curse on its own.  This usually happens during a life and death situation, although it will settle for making social situations disastrously awkward and possibly life-threatening.  It prefers to endanger innocents when available, but in a pinch it will settle for one of your allies instead.

Sometimes it doesn't wait a whole week, either.

If you truly, sincerely wish to take back a curse laid using the tooth you just need to say so.  The curse stays in effect regardless of your wishes, but you also get cursed in the process.  You'll also painfully bite your tongue in the process to add injury to, well, injury.        

Design Commentary:  This is a very fairy-tale item as written.  You could make it more mundane by associating them with your common everyday hags, but I'd tone the power level and complications down some if you do so.  Either way, Grandmother's Hexing Tooth isn't a unique item, quite a lot of them have been gifted to people over time.  It's remotely possible you might run into someone else with one.  Maybe more than one.  Maybe some psychopath is trying to collect a whole mouthful of them.  That could make for an interesting story arc.

It's also quite possible that Grandmother has teeth that do other things too.  Some of those things might not even be awful.