An Arkanythera Mechanism, known also as the “spell turner” is a finely crafted device designed to interrupt hostile spellcasting. Intricate clockwork is inscribed with runes representing the three moons, forces of Law and Chaos, as well as each of the base elements. In the hands of an expert they are a potent device for countering sorcery.

With this device in hand you can ready to disrupt magic. This is an intelligence check requiring proficiency in both Arcana and thieves’ tools to be proficient in, opposed by a proficiency + spellcasting ability check of the caster.

Beat caster by 10+Spell targets caster instead of intended target
Beat casterAs above, but device gains charges equal to spell level
TieSpell held in flux, check repeated next round, gain 1 charge
Caster winsSpell operates as normal, gain 1 charge
Caster wins by 10+Spell operates as normal, caster may choose to have spell affect the user in addition, gains 1d6 charges

Due to the volatility of magic the device accrues chaotic arcane energy, charges, as it is used. Each time charge is gained roll 1d20, if this roll is lower than or equal to the current number of charges the device explodes. This deals (charges)d6 damage to the user. Charge is dispersed when the blue moon sets.