Detestable Sandals

A magical item from the Elderdays, Detestable Sandals can align with a creature of sufficient magical ability to destroy the mundane. Only a creature that can cast spells (magician) can attempt to align with Detestable Sandals. A creature may seek to align Detestable Sandals by spending 10 minutes holding the Sandals in quiet contemplation (i.e. no movement, no actions, no bonus actions, no reactions, no interaction with the world around them) and making a DC 18 intelligence, wisdom or charisma save at the end of the contemplation (whichever is the best).

On a failure, the magician takes 2d8 psychic damage or 2d8 radiant damage (whichever will cause the most damage) and no creature can seek to align the Detestable Sandals again for 24 hours (the failed aligner for one year)
On a success, the magician aligns with Detestable Sandals for a period of days equal to the magician's proficiency bonus
Using a reaction, the magician can activate the Sandals and deal maximum damage with a spell to any non-magician it affects
Any other magician's affected by the aligned magician's spell take damage as normal
The aligned magician takes the difference in damage between the maximum damage dealt to non-magicians and the damage dealt to magicians via the damage type of the spell
Damage to the magician dealt this way ignores temporary hit points and may not be redirected, reduced or prevented by other means
Once activated the Detestable Sandals deactivate and reappear within d6 miles x the aligners proficiency bonus within a period of time equal to d3 x magician's proficiency bonus
A magician that has previously aligned with Detestable Sandals cannot attempt to realign with any Detestable Sandals for seven long rests

"To live is to hurt others, and through others, to hurt oneself."