C is for Punch Daggers!

This item comes from a campaign that uses both D&D 5th edition rules and AD&D 2nd edition non-weapon proficiencies and psionics. YMMV.

Sphaṭika Gim̐ṭa (The Crystal Knuckles)

The Sphaṭika Gim̐ṭa is an ancient weapon of unknown origin. It resembles four interconnected mythril rings sprouting a mass of clear, quartz crystal, with longer, dagger-like projections of crystal on either end. Held by fingers slotted through the rings, it can be used to add "interest" to a punch, much like a katar or brass knuckles. Some sages speculate the the crystal projections were grown in place on the rings, rather than attached artificially, suggesting powerful magic or extraplanar forces involved in their creation. Despite these theories, the Sphaṭika Gim̐ṭa does not radiate magic.

The "crystal knuckles" as they are commonly called, first appear in the records of the eastern kingdoms of Impiltur in the year 627 DR. Tales from the courts of King Imphras claim that the king's great-great-great-grandfather found the strange items on the shores of the River Icehilt, near what is now known as the Shimmerglade (a region known for considerable Fey activity). The crystal knuckles were passed down with the family treasures, and thence into the royal treasury of Impiltur after the founding of the Imphram dynasty. The royal records say that the knuckles were gifted to a knight by the name of Taeren Swifthelm in the Year of the Cloven Stones (1159 DR) by the then queen Saphrae for "services rendered". No records of the item exist after that, and the royal court records say nothing of any uses of the item, save for its ornamental value.

In the hands of most users, the crystal knuckles add +1 to the damage of any unarmed attacks made while wearing them. The Sphaṭika Gim̐ṭa does possess other unusual powers, but it does not radiate magic, nor does it give up its secrets to identify or similar spells.

When the Sphaṭika Gim̐ṭa is handled by any "enlightened being" (any creature with psionic abilities or with a Wisdom score of 19 or greater), the person handling the item immediately becomes aware of the following functions.

• First, whenever it is worn by an "enlightened individual" (as defined above) the knuckles generates a constant "hum" of telepathic interference. Creatures attempting to use telepathic communication while within 60 feet of the user find the range of such communication halved. Likewise, anyone attempting to use Psionic powers from the telepathic discipline while within 60 feet must expend 2x the normal number of power points. The person wearing the Sphaṭika Gim̐ṭa is not subject to these penalties.
• Any strike made with the Sphaṭika Gim̐ṭa is treated as magical and adamantine for the purpose of determining what creatures can be harmed by it. In addition, any successful strike against a psionic creature drains 1d6 power points from the target. Any strike on a creature with ki points, sorcery points, or some other limited-use pool of magical energy (excluding spell slots) drains 1 point per hit. This drain is doubled on a critical hit, just as normal damage would be.
• By focusing his own power into the Sphaṭika Gim̐ṭa, the user can expand his senses outward into the Cosmos. By expending 5 ki points or sorcerery points, or 20 psionic power points, the user can gain the benefits of a Contact Other Plane spell. This takes 10 minutes, during which time the user is considered incapacitated.
• Lastly, an enlightened user gains the benefits of the Chaos Shaping proficiency (see the Planewalker's Handbook) as long as Sphaṭika Gim̐ṭa is worn.