Gavel of the Venn Rune

From Storm King's Thunder, page 234.

Description
Wondrous item, rare (requires attunement).

This wooden gavel is small by giant reckoning but nearly the size of a warhammer in human hands. The venn (friend) rune is inscribed in mithral in the base of the haft. Among giants, this item is used as part of rituals to resolve disputes. The gavel has the following properties.

Arbiters Shield. At the start of every combat, attack rolls against you have disadvantage before the start of your first turn, provided that the gavel is on your person.

Bond of Amity. As an action, you can use the gavel to strike a point on a hard surface. The first time in the next minute that a creature within 60 feet of that point deals damage to another creature with an attack that hits, the attacker takes psychic damage equal to half the damage it dealt to the target. Once you use this property, you can't use it again until you finish a long rest.

Gift of Truth. You can transfer the gavel's magic to a place by tracing the venn rune on the ground with your finger. The point where you trace it becomes the center of a spherical area of magic that has a 30-foot radius and that is fixed to the place. The transfer takes 8 hours of work that requires the gavel to be within 5 feet of you. At the end, the gavel is destroyed, and the area gains the following property:

Whenever a creature utters a lie while within the 30-foot-radius sphere, that creature takes 5 psychic damage and flinches visibly.