Lightning Diadem

Wondrous item, rare (requires attunement) Price: 5,000-10,000 gp | medium sentimentality

This diadem is made of crackling lightning but can be held as though made of metal. While you wear the diadem, any creature that hits you with a melee attack must succeed a DC 14 Constitution check or suffer 1d4 lightning damage.

Paid

While you wear the diadem, creatures within 5 feet of you that suffer lightning damage also suffer 1d4 thunder damage.

Overpaid

You have resistance to lightning damage.

Source: The Gray Merchant of Asphodel