Rod of Reverberation

This rod bears the embossed likeness of an ox at its top, where it splits into two horn-like prongs. When struck, the prongs reverberate with a magical force and electricity.

The rod has 3 charges and regains all expended charges daily at dawn. While holding the rod, you can use your reaction when another creature hits you with a melee attack to expend 1 of the rod's charges to increase your AC by 1d6 for that attack, potentially causing the attack to miss you. If the attack misses you as a result of using this property, the attacker must also make a DC 15 Constitution saving throw. On a failed save, the creature takes 1d10 lightning damage and 1d10 thunder damage and has disadvantage on the next attack roll it makes before the end of its next turn. On a successful save, the creature takes half as much damage and makes its next attack as normal.